xref: /openbmc/linux/fs/btrfs/disk-io.c (revision 6774def6)
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 "locking.h"
43 #include "tree-log.h"
44 #include "free-space-cache.h"
45 #include "inode-map.h"
46 #include "check-integrity.h"
47 #include "rcu-string.h"
48 #include "dev-replace.h"
49 #include "raid56.h"
50 #include "sysfs.h"
51 #include "qgroup.h"
52 
53 #ifdef CONFIG_X86
54 #include <asm/cpufeature.h>
55 #endif
56 
57 static struct extent_io_ops btree_extent_io_ops;
58 static void end_workqueue_fn(struct btrfs_work *work);
59 static void free_fs_root(struct btrfs_root *root);
60 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
61 				    int read_only);
62 static void btrfs_destroy_ordered_extents(struct btrfs_root *root);
63 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
64 				      struct btrfs_root *root);
65 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
66 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
67 					struct extent_io_tree *dirty_pages,
68 					int mark);
69 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
70 				       struct extent_io_tree *pinned_extents);
71 static int btrfs_cleanup_transaction(struct btrfs_root *root);
72 static void btrfs_error_commit_super(struct btrfs_root *root);
73 
74 /*
75  * btrfs_end_io_wq structs are used to do processing in task context when an IO
76  * is complete.  This is used during reads to verify checksums, and it is used
77  * by writes to insert metadata for new file extents after IO is complete.
78  */
79 struct btrfs_end_io_wq {
80 	struct bio *bio;
81 	bio_end_io_t *end_io;
82 	void *private;
83 	struct btrfs_fs_info *info;
84 	int error;
85 	enum btrfs_wq_endio_type metadata;
86 	struct list_head list;
87 	struct btrfs_work work;
88 };
89 
90 static struct kmem_cache *btrfs_end_io_wq_cache;
91 
92 int __init btrfs_end_io_wq_init(void)
93 {
94 	btrfs_end_io_wq_cache = kmem_cache_create("btrfs_end_io_wq",
95 					sizeof(struct btrfs_end_io_wq),
96 					0,
97 					SLAB_RECLAIM_ACCOUNT | SLAB_MEM_SPREAD,
98 					NULL);
99 	if (!btrfs_end_io_wq_cache)
100 		return -ENOMEM;
101 	return 0;
102 }
103 
104 void btrfs_end_io_wq_exit(void)
105 {
106 	if (btrfs_end_io_wq_cache)
107 		kmem_cache_destroy(btrfs_end_io_wq_cache);
108 }
109 
110 /*
111  * async submit bios are used to offload expensive checksumming
112  * onto the worker threads.  They checksum file and metadata bios
113  * just before they are sent down the IO stack.
114  */
115 struct async_submit_bio {
116 	struct inode *inode;
117 	struct bio *bio;
118 	struct list_head list;
119 	extent_submit_bio_hook_t *submit_bio_start;
120 	extent_submit_bio_hook_t *submit_bio_done;
121 	int rw;
122 	int mirror_num;
123 	unsigned long bio_flags;
124 	/*
125 	 * bio_offset is optional, can be used if the pages in the bio
126 	 * can't tell us where in the file the bio should go
127 	 */
128 	u64 bio_offset;
129 	struct btrfs_work work;
130 	int error;
131 };
132 
133 /*
134  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
135  * eb, the lockdep key is determined by the btrfs_root it belongs to and
136  * the level the eb occupies in the tree.
137  *
138  * Different roots are used for different purposes and may nest inside each
139  * other and they require separate keysets.  As lockdep keys should be
140  * static, assign keysets according to the purpose of the root as indicated
141  * by btrfs_root->objectid.  This ensures that all special purpose roots
142  * have separate keysets.
143  *
144  * Lock-nesting across peer nodes is always done with the immediate parent
145  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
146  * subclass to avoid triggering lockdep warning in such cases.
147  *
148  * The key is set by the readpage_end_io_hook after the buffer has passed
149  * csum validation but before the pages are unlocked.  It is also set by
150  * btrfs_init_new_buffer on freshly allocated blocks.
151  *
152  * We also add a check to make sure the highest level of the tree is the
153  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
154  * needs update as well.
155  */
156 #ifdef CONFIG_DEBUG_LOCK_ALLOC
157 # if BTRFS_MAX_LEVEL != 8
158 #  error
159 # endif
160 
161 static struct btrfs_lockdep_keyset {
162 	u64			id;		/* root objectid */
163 	const char		*name_stem;	/* lock name stem */
164 	char			names[BTRFS_MAX_LEVEL + 1][20];
165 	struct lock_class_key	keys[BTRFS_MAX_LEVEL + 1];
166 } btrfs_lockdep_keysets[] = {
167 	{ .id = BTRFS_ROOT_TREE_OBJECTID,	.name_stem = "root"	},
168 	{ .id = BTRFS_EXTENT_TREE_OBJECTID,	.name_stem = "extent"	},
169 	{ .id = BTRFS_CHUNK_TREE_OBJECTID,	.name_stem = "chunk"	},
170 	{ .id = BTRFS_DEV_TREE_OBJECTID,	.name_stem = "dev"	},
171 	{ .id = BTRFS_FS_TREE_OBJECTID,		.name_stem = "fs"	},
172 	{ .id = BTRFS_CSUM_TREE_OBJECTID,	.name_stem = "csum"	},
173 	{ .id = BTRFS_QUOTA_TREE_OBJECTID,	.name_stem = "quota"	},
174 	{ .id = BTRFS_TREE_LOG_OBJECTID,	.name_stem = "log"	},
175 	{ .id = BTRFS_TREE_RELOC_OBJECTID,	.name_stem = "treloc"	},
176 	{ .id = BTRFS_DATA_RELOC_TREE_OBJECTID,	.name_stem = "dreloc"	},
177 	{ .id = BTRFS_UUID_TREE_OBJECTID,	.name_stem = "uuid"	},
178 	{ .id = 0,				.name_stem = "tree"	},
179 };
180 
181 void __init btrfs_init_lockdep(void)
182 {
183 	int i, j;
184 
185 	/* initialize lockdep class names */
186 	for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
187 		struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
188 
189 		for (j = 0; j < ARRAY_SIZE(ks->names); j++)
190 			snprintf(ks->names[j], sizeof(ks->names[j]),
191 				 "btrfs-%s-%02d", ks->name_stem, j);
192 	}
193 }
194 
195 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
196 				    int level)
197 {
198 	struct btrfs_lockdep_keyset *ks;
199 
200 	BUG_ON(level >= ARRAY_SIZE(ks->keys));
201 
202 	/* find the matching keyset, id 0 is the default entry */
203 	for (ks = btrfs_lockdep_keysets; ks->id; ks++)
204 		if (ks->id == objectid)
205 			break;
206 
207 	lockdep_set_class_and_name(&eb->lock,
208 				   &ks->keys[level], ks->names[level]);
209 }
210 
211 #endif
212 
213 /*
214  * extents on the btree inode are pretty simple, there's one extent
215  * that covers the entire device
216  */
217 static struct extent_map *btree_get_extent(struct inode *inode,
218 		struct page *page, size_t pg_offset, u64 start, u64 len,
219 		int create)
220 {
221 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
222 	struct extent_map *em;
223 	int ret;
224 
225 	read_lock(&em_tree->lock);
226 	em = lookup_extent_mapping(em_tree, start, len);
227 	if (em) {
228 		em->bdev =
229 			BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
230 		read_unlock(&em_tree->lock);
231 		goto out;
232 	}
233 	read_unlock(&em_tree->lock);
234 
235 	em = alloc_extent_map();
236 	if (!em) {
237 		em = ERR_PTR(-ENOMEM);
238 		goto out;
239 	}
240 	em->start = 0;
241 	em->len = (u64)-1;
242 	em->block_len = (u64)-1;
243 	em->block_start = 0;
244 	em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
245 
246 	write_lock(&em_tree->lock);
247 	ret = add_extent_mapping(em_tree, em, 0);
248 	if (ret == -EEXIST) {
249 		free_extent_map(em);
250 		em = lookup_extent_mapping(em_tree, start, len);
251 		if (!em)
252 			em = ERR_PTR(-EIO);
253 	} else if (ret) {
254 		free_extent_map(em);
255 		em = ERR_PTR(ret);
256 	}
257 	write_unlock(&em_tree->lock);
258 
259 out:
260 	return em;
261 }
262 
263 u32 btrfs_csum_data(char *data, u32 seed, size_t len)
264 {
265 	return btrfs_crc32c(seed, data, len);
266 }
267 
268 void btrfs_csum_final(u32 crc, char *result)
269 {
270 	put_unaligned_le32(~crc, result);
271 }
272 
273 /*
274  * compute the csum for a btree block, and either verify it or write it
275  * into the csum field of the block.
276  */
277 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
278 			   int verify)
279 {
280 	u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
281 	char *result = NULL;
282 	unsigned long len;
283 	unsigned long cur_len;
284 	unsigned long offset = BTRFS_CSUM_SIZE;
285 	char *kaddr;
286 	unsigned long map_start;
287 	unsigned long map_len;
288 	int err;
289 	u32 crc = ~(u32)0;
290 	unsigned long inline_result;
291 
292 	len = buf->len - offset;
293 	while (len > 0) {
294 		err = map_private_extent_buffer(buf, offset, 32,
295 					&kaddr, &map_start, &map_len);
296 		if (err)
297 			return 1;
298 		cur_len = min(len, map_len - (offset - map_start));
299 		crc = btrfs_csum_data(kaddr + offset - map_start,
300 				      crc, cur_len);
301 		len -= cur_len;
302 		offset += cur_len;
303 	}
304 	if (csum_size > sizeof(inline_result)) {
305 		result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
306 		if (!result)
307 			return 1;
308 	} else {
309 		result = (char *)&inline_result;
310 	}
311 
312 	btrfs_csum_final(crc, result);
313 
314 	if (verify) {
315 		if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
316 			u32 val;
317 			u32 found = 0;
318 			memcpy(&found, result, csum_size);
319 
320 			read_extent_buffer(buf, &val, 0, csum_size);
321 			printk_ratelimited(KERN_INFO
322 				"BTRFS: %s checksum verify failed on %llu wanted %X found %X "
323 				"level %d\n",
324 				root->fs_info->sb->s_id, buf->start,
325 				val, found, btrfs_header_level(buf));
326 			if (result != (char *)&inline_result)
327 				kfree(result);
328 			return 1;
329 		}
330 	} else {
331 		write_extent_buffer(buf, result, 0, csum_size);
332 	}
333 	if (result != (char *)&inline_result)
334 		kfree(result);
335 	return 0;
336 }
337 
338 /*
339  * we can't consider a given block up to date unless the transid of the
340  * block matches the transid in the parent node's pointer.  This is how we
341  * detect blocks that either didn't get written at all or got written
342  * in the wrong place.
343  */
344 static int verify_parent_transid(struct extent_io_tree *io_tree,
345 				 struct extent_buffer *eb, u64 parent_transid,
346 				 int atomic)
347 {
348 	struct extent_state *cached_state = NULL;
349 	int ret;
350 	bool need_lock = (current->journal_info == BTRFS_SEND_TRANS_STUB);
351 
352 	if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
353 		return 0;
354 
355 	if (atomic)
356 		return -EAGAIN;
357 
358 	if (need_lock) {
359 		btrfs_tree_read_lock(eb);
360 		btrfs_set_lock_blocking_rw(eb, BTRFS_READ_LOCK);
361 	}
362 
363 	lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
364 			 0, &cached_state);
365 	if (extent_buffer_uptodate(eb) &&
366 	    btrfs_header_generation(eb) == parent_transid) {
367 		ret = 0;
368 		goto out;
369 	}
370 	printk_ratelimited(KERN_INFO "BTRFS (device %s): parent transid verify failed on %llu wanted %llu found %llu\n",
371 			eb->fs_info->sb->s_id, eb->start,
372 			parent_transid, btrfs_header_generation(eb));
373 	ret = 1;
374 
375 	/*
376 	 * Things reading via commit roots that don't have normal protection,
377 	 * like send, can have a really old block in cache that may point at a
378 	 * block that has been free'd and re-allocated.  So don't clear uptodate
379 	 * if we find an eb that is under IO (dirty/writeback) because we could
380 	 * end up reading in the stale data and then writing it back out and
381 	 * making everybody very sad.
382 	 */
383 	if (!extent_buffer_under_io(eb))
384 		clear_extent_buffer_uptodate(eb);
385 out:
386 	unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
387 			     &cached_state, GFP_NOFS);
388 	if (need_lock)
389 		btrfs_tree_read_unlock_blocking(eb);
390 	return ret;
391 }
392 
393 /*
394  * Return 0 if the superblock checksum type matches the checksum value of that
395  * algorithm. Pass the raw disk superblock data.
396  */
397 static int btrfs_check_super_csum(char *raw_disk_sb)
398 {
399 	struct btrfs_super_block *disk_sb =
400 		(struct btrfs_super_block *)raw_disk_sb;
401 	u16 csum_type = btrfs_super_csum_type(disk_sb);
402 	int ret = 0;
403 
404 	if (csum_type == BTRFS_CSUM_TYPE_CRC32) {
405 		u32 crc = ~(u32)0;
406 		const int csum_size = sizeof(crc);
407 		char result[csum_size];
408 
409 		/*
410 		 * The super_block structure does not span the whole
411 		 * BTRFS_SUPER_INFO_SIZE range, we expect that the unused space
412 		 * is filled with zeros and is included in the checkum.
413 		 */
414 		crc = btrfs_csum_data(raw_disk_sb + BTRFS_CSUM_SIZE,
415 				crc, BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
416 		btrfs_csum_final(crc, result);
417 
418 		if (memcmp(raw_disk_sb, result, csum_size))
419 			ret = 1;
420 
421 		if (ret && btrfs_super_generation(disk_sb) < 10) {
422 			printk(KERN_WARNING
423 				"BTRFS: super block crcs don't match, older mkfs detected\n");
424 			ret = 0;
425 		}
426 	}
427 
428 	if (csum_type >= ARRAY_SIZE(btrfs_csum_sizes)) {
429 		printk(KERN_ERR "BTRFS: unsupported checksum algorithm %u\n",
430 				csum_type);
431 		ret = 1;
432 	}
433 
434 	return ret;
435 }
436 
437 /*
438  * helper to read a given tree block, doing retries as required when
439  * the checksums don't match and we have alternate mirrors to try.
440  */
441 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
442 					  struct extent_buffer *eb,
443 					  u64 start, u64 parent_transid)
444 {
445 	struct extent_io_tree *io_tree;
446 	int failed = 0;
447 	int ret;
448 	int num_copies = 0;
449 	int mirror_num = 0;
450 	int failed_mirror = 0;
451 
452 	clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
453 	io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
454 	while (1) {
455 		ret = read_extent_buffer_pages(io_tree, eb, start,
456 					       WAIT_COMPLETE,
457 					       btree_get_extent, mirror_num);
458 		if (!ret) {
459 			if (!verify_parent_transid(io_tree, eb,
460 						   parent_transid, 0))
461 				break;
462 			else
463 				ret = -EIO;
464 		}
465 
466 		/*
467 		 * This buffer's crc is fine, but its contents are corrupted, so
468 		 * there is no reason to read the other copies, they won't be
469 		 * any less wrong.
470 		 */
471 		if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
472 			break;
473 
474 		num_copies = btrfs_num_copies(root->fs_info,
475 					      eb->start, eb->len);
476 		if (num_copies == 1)
477 			break;
478 
479 		if (!failed_mirror) {
480 			failed = 1;
481 			failed_mirror = eb->read_mirror;
482 		}
483 
484 		mirror_num++;
485 		if (mirror_num == failed_mirror)
486 			mirror_num++;
487 
488 		if (mirror_num > num_copies)
489 			break;
490 	}
491 
492 	if (failed && !ret && failed_mirror)
493 		repair_eb_io_failure(root, eb, failed_mirror);
494 
495 	return ret;
496 }
497 
498 /*
499  * checksum a dirty tree block before IO.  This has extra checks to make sure
500  * we only fill in the checksum field in the first page of a multi-page block
501  */
502 
503 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
504 {
505 	u64 start = page_offset(page);
506 	u64 found_start;
507 	struct extent_buffer *eb;
508 
509 	eb = (struct extent_buffer *)page->private;
510 	if (page != eb->pages[0])
511 		return 0;
512 	found_start = btrfs_header_bytenr(eb);
513 	if (WARN_ON(found_start != start || !PageUptodate(page)))
514 		return 0;
515 	csum_tree_block(root, eb, 0);
516 	return 0;
517 }
518 
519 static int check_tree_block_fsid(struct btrfs_root *root,
520 				 struct extent_buffer *eb)
521 {
522 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
523 	u8 fsid[BTRFS_UUID_SIZE];
524 	int ret = 1;
525 
526 	read_extent_buffer(eb, fsid, btrfs_header_fsid(), BTRFS_FSID_SIZE);
527 	while (fs_devices) {
528 		if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
529 			ret = 0;
530 			break;
531 		}
532 		fs_devices = fs_devices->seed;
533 	}
534 	return ret;
535 }
536 
537 #define CORRUPT(reason, eb, root, slot)				\
538 	btrfs_crit(root->fs_info, "corrupt leaf, %s: block=%llu,"	\
539 		   "root=%llu, slot=%d", reason,			\
540 	       btrfs_header_bytenr(eb),	root->objectid, slot)
541 
542 static noinline int check_leaf(struct btrfs_root *root,
543 			       struct extent_buffer *leaf)
544 {
545 	struct btrfs_key key;
546 	struct btrfs_key leaf_key;
547 	u32 nritems = btrfs_header_nritems(leaf);
548 	int slot;
549 
550 	if (nritems == 0)
551 		return 0;
552 
553 	/* Check the 0 item */
554 	if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
555 	    BTRFS_LEAF_DATA_SIZE(root)) {
556 		CORRUPT("invalid item offset size pair", leaf, root, 0);
557 		return -EIO;
558 	}
559 
560 	/*
561 	 * Check to make sure each items keys are in the correct order and their
562 	 * offsets make sense.  We only have to loop through nritems-1 because
563 	 * we check the current slot against the next slot, which verifies the
564 	 * next slot's offset+size makes sense and that the current's slot
565 	 * offset is correct.
566 	 */
567 	for (slot = 0; slot < nritems - 1; slot++) {
568 		btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
569 		btrfs_item_key_to_cpu(leaf, &key, slot + 1);
570 
571 		/* Make sure the keys are in the right order */
572 		if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
573 			CORRUPT("bad key order", leaf, root, slot);
574 			return -EIO;
575 		}
576 
577 		/*
578 		 * Make sure the offset and ends are right, remember that the
579 		 * item data starts at the end of the leaf and grows towards the
580 		 * front.
581 		 */
582 		if (btrfs_item_offset_nr(leaf, slot) !=
583 			btrfs_item_end_nr(leaf, slot + 1)) {
584 			CORRUPT("slot offset bad", leaf, root, slot);
585 			return -EIO;
586 		}
587 
588 		/*
589 		 * Check to make sure that we don't point outside of the leaf,
590 		 * just incase all the items are consistent to eachother, but
591 		 * all point outside of the leaf.
592 		 */
593 		if (btrfs_item_end_nr(leaf, slot) >
594 		    BTRFS_LEAF_DATA_SIZE(root)) {
595 			CORRUPT("slot end outside of leaf", leaf, root, slot);
596 			return -EIO;
597 		}
598 	}
599 
600 	return 0;
601 }
602 
603 static int btree_readpage_end_io_hook(struct btrfs_io_bio *io_bio,
604 				      u64 phy_offset, struct page *page,
605 				      u64 start, u64 end, int mirror)
606 {
607 	u64 found_start;
608 	int found_level;
609 	struct extent_buffer *eb;
610 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
611 	int ret = 0;
612 	int reads_done;
613 
614 	if (!page->private)
615 		goto out;
616 
617 	eb = (struct extent_buffer *)page->private;
618 
619 	/* the pending IO might have been the only thing that kept this buffer
620 	 * in memory.  Make sure we have a ref for all this other checks
621 	 */
622 	extent_buffer_get(eb);
623 
624 	reads_done = atomic_dec_and_test(&eb->io_pages);
625 	if (!reads_done)
626 		goto err;
627 
628 	eb->read_mirror = mirror;
629 	if (test_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags)) {
630 		ret = -EIO;
631 		goto err;
632 	}
633 
634 	found_start = btrfs_header_bytenr(eb);
635 	if (found_start != eb->start) {
636 		printk_ratelimited(KERN_INFO "BTRFS (device %s): bad tree block start "
637 			       "%llu %llu\n",
638 			       eb->fs_info->sb->s_id, found_start, eb->start);
639 		ret = -EIO;
640 		goto err;
641 	}
642 	if (check_tree_block_fsid(root, eb)) {
643 		printk_ratelimited(KERN_INFO "BTRFS (device %s): bad fsid on block %llu\n",
644 			       eb->fs_info->sb->s_id, eb->start);
645 		ret = -EIO;
646 		goto err;
647 	}
648 	found_level = btrfs_header_level(eb);
649 	if (found_level >= BTRFS_MAX_LEVEL) {
650 		btrfs_info(root->fs_info, "bad tree block level %d",
651 			   (int)btrfs_header_level(eb));
652 		ret = -EIO;
653 		goto err;
654 	}
655 
656 	btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
657 				       eb, found_level);
658 
659 	ret = csum_tree_block(root, eb, 1);
660 	if (ret) {
661 		ret = -EIO;
662 		goto err;
663 	}
664 
665 	/*
666 	 * If this is a leaf block and it is corrupt, set the corrupt bit so
667 	 * that we don't try and read the other copies of this block, just
668 	 * return -EIO.
669 	 */
670 	if (found_level == 0 && check_leaf(root, eb)) {
671 		set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
672 		ret = -EIO;
673 	}
674 
675 	if (!ret)
676 		set_extent_buffer_uptodate(eb);
677 err:
678 	if (reads_done &&
679 	    test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
680 		btree_readahead_hook(root, eb, eb->start, ret);
681 
682 	if (ret) {
683 		/*
684 		 * our io error hook is going to dec the io pages
685 		 * again, we have to make sure it has something
686 		 * to decrement
687 		 */
688 		atomic_inc(&eb->io_pages);
689 		clear_extent_buffer_uptodate(eb);
690 	}
691 	free_extent_buffer(eb);
692 out:
693 	return ret;
694 }
695 
696 static int btree_io_failed_hook(struct page *page, int failed_mirror)
697 {
698 	struct extent_buffer *eb;
699 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
700 
701 	eb = (struct extent_buffer *)page->private;
702 	set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
703 	eb->read_mirror = failed_mirror;
704 	atomic_dec(&eb->io_pages);
705 	if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
706 		btree_readahead_hook(root, eb, eb->start, -EIO);
707 	return -EIO;	/* we fixed nothing */
708 }
709 
710 static void end_workqueue_bio(struct bio *bio, int err)
711 {
712 	struct btrfs_end_io_wq *end_io_wq = bio->bi_private;
713 	struct btrfs_fs_info *fs_info;
714 	struct btrfs_workqueue *wq;
715 	btrfs_work_func_t func;
716 
717 	fs_info = end_io_wq->info;
718 	end_io_wq->error = err;
719 
720 	if (bio->bi_rw & REQ_WRITE) {
721 		if (end_io_wq->metadata == BTRFS_WQ_ENDIO_METADATA) {
722 			wq = fs_info->endio_meta_write_workers;
723 			func = btrfs_endio_meta_write_helper;
724 		} else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_FREE_SPACE) {
725 			wq = fs_info->endio_freespace_worker;
726 			func = btrfs_freespace_write_helper;
727 		} else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
728 			wq = fs_info->endio_raid56_workers;
729 			func = btrfs_endio_raid56_helper;
730 		} else {
731 			wq = fs_info->endio_write_workers;
732 			func = btrfs_endio_write_helper;
733 		}
734 	} else {
735 		if (unlikely(end_io_wq->metadata ==
736 			     BTRFS_WQ_ENDIO_DIO_REPAIR)) {
737 			wq = fs_info->endio_repair_workers;
738 			func = btrfs_endio_repair_helper;
739 		} else if (end_io_wq->metadata == BTRFS_WQ_ENDIO_RAID56) {
740 			wq = fs_info->endio_raid56_workers;
741 			func = btrfs_endio_raid56_helper;
742 		} else if (end_io_wq->metadata) {
743 			wq = fs_info->endio_meta_workers;
744 			func = btrfs_endio_meta_helper;
745 		} else {
746 			wq = fs_info->endio_workers;
747 			func = btrfs_endio_helper;
748 		}
749 	}
750 
751 	btrfs_init_work(&end_io_wq->work, func, end_workqueue_fn, NULL, NULL);
752 	btrfs_queue_work(wq, &end_io_wq->work);
753 }
754 
755 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
756 			enum btrfs_wq_endio_type metadata)
757 {
758 	struct btrfs_end_io_wq *end_io_wq;
759 
760 	end_io_wq = kmem_cache_alloc(btrfs_end_io_wq_cache, GFP_NOFS);
761 	if (!end_io_wq)
762 		return -ENOMEM;
763 
764 	end_io_wq->private = bio->bi_private;
765 	end_io_wq->end_io = bio->bi_end_io;
766 	end_io_wq->info = info;
767 	end_io_wq->error = 0;
768 	end_io_wq->bio = bio;
769 	end_io_wq->metadata = metadata;
770 
771 	bio->bi_private = end_io_wq;
772 	bio->bi_end_io = end_workqueue_bio;
773 	return 0;
774 }
775 
776 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
777 {
778 	unsigned long limit = min_t(unsigned long,
779 				    info->thread_pool_size,
780 				    info->fs_devices->open_devices);
781 	return 256 * limit;
782 }
783 
784 static void run_one_async_start(struct btrfs_work *work)
785 {
786 	struct async_submit_bio *async;
787 	int ret;
788 
789 	async = container_of(work, struct  async_submit_bio, work);
790 	ret = async->submit_bio_start(async->inode, async->rw, async->bio,
791 				      async->mirror_num, async->bio_flags,
792 				      async->bio_offset);
793 	if (ret)
794 		async->error = ret;
795 }
796 
797 static void run_one_async_done(struct btrfs_work *work)
798 {
799 	struct btrfs_fs_info *fs_info;
800 	struct async_submit_bio *async;
801 	int limit;
802 
803 	async = container_of(work, struct  async_submit_bio, work);
804 	fs_info = BTRFS_I(async->inode)->root->fs_info;
805 
806 	limit = btrfs_async_submit_limit(fs_info);
807 	limit = limit * 2 / 3;
808 
809 	if (atomic_dec_return(&fs_info->nr_async_submits) < limit &&
810 	    waitqueue_active(&fs_info->async_submit_wait))
811 		wake_up(&fs_info->async_submit_wait);
812 
813 	/* If an error occured we just want to clean up the bio and move on */
814 	if (async->error) {
815 		bio_endio(async->bio, async->error);
816 		return;
817 	}
818 
819 	async->submit_bio_done(async->inode, async->rw, async->bio,
820 			       async->mirror_num, async->bio_flags,
821 			       async->bio_offset);
822 }
823 
824 static void run_one_async_free(struct btrfs_work *work)
825 {
826 	struct async_submit_bio *async;
827 
828 	async = container_of(work, struct  async_submit_bio, work);
829 	kfree(async);
830 }
831 
832 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
833 			int rw, struct bio *bio, int mirror_num,
834 			unsigned long bio_flags,
835 			u64 bio_offset,
836 			extent_submit_bio_hook_t *submit_bio_start,
837 			extent_submit_bio_hook_t *submit_bio_done)
838 {
839 	struct async_submit_bio *async;
840 
841 	async = kmalloc(sizeof(*async), GFP_NOFS);
842 	if (!async)
843 		return -ENOMEM;
844 
845 	async->inode = inode;
846 	async->rw = rw;
847 	async->bio = bio;
848 	async->mirror_num = mirror_num;
849 	async->submit_bio_start = submit_bio_start;
850 	async->submit_bio_done = submit_bio_done;
851 
852 	btrfs_init_work(&async->work, btrfs_worker_helper, run_one_async_start,
853 			run_one_async_done, run_one_async_free);
854 
855 	async->bio_flags = bio_flags;
856 	async->bio_offset = bio_offset;
857 
858 	async->error = 0;
859 
860 	atomic_inc(&fs_info->nr_async_submits);
861 
862 	if (rw & REQ_SYNC)
863 		btrfs_set_work_high_priority(&async->work);
864 
865 	btrfs_queue_work(fs_info->workers, &async->work);
866 
867 	while (atomic_read(&fs_info->async_submit_draining) &&
868 	      atomic_read(&fs_info->nr_async_submits)) {
869 		wait_event(fs_info->async_submit_wait,
870 			   (atomic_read(&fs_info->nr_async_submits) == 0));
871 	}
872 
873 	return 0;
874 }
875 
876 static int btree_csum_one_bio(struct bio *bio)
877 {
878 	struct bio_vec *bvec;
879 	struct btrfs_root *root;
880 	int i, ret = 0;
881 
882 	bio_for_each_segment_all(bvec, bio, i) {
883 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
884 		ret = csum_dirty_buffer(root, bvec->bv_page);
885 		if (ret)
886 			break;
887 	}
888 
889 	return ret;
890 }
891 
892 static int __btree_submit_bio_start(struct inode *inode, int rw,
893 				    struct bio *bio, int mirror_num,
894 				    unsigned long bio_flags,
895 				    u64 bio_offset)
896 {
897 	/*
898 	 * when we're called for a write, we're already in the async
899 	 * submission context.  Just jump into btrfs_map_bio
900 	 */
901 	return btree_csum_one_bio(bio);
902 }
903 
904 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
905 				 int mirror_num, unsigned long bio_flags,
906 				 u64 bio_offset)
907 {
908 	int ret;
909 
910 	/*
911 	 * when we're called for a write, we're already in the async
912 	 * submission context.  Just jump into btrfs_map_bio
913 	 */
914 	ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
915 	if (ret)
916 		bio_endio(bio, ret);
917 	return ret;
918 }
919 
920 static int check_async_write(struct inode *inode, unsigned long bio_flags)
921 {
922 	if (bio_flags & EXTENT_BIO_TREE_LOG)
923 		return 0;
924 #ifdef CONFIG_X86
925 	if (cpu_has_xmm4_2)
926 		return 0;
927 #endif
928 	return 1;
929 }
930 
931 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
932 				 int mirror_num, unsigned long bio_flags,
933 				 u64 bio_offset)
934 {
935 	int async = check_async_write(inode, bio_flags);
936 	int ret;
937 
938 	if (!(rw & REQ_WRITE)) {
939 		/*
940 		 * called for a read, do the setup so that checksum validation
941 		 * can happen in the async kernel threads
942 		 */
943 		ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
944 					  bio, BTRFS_WQ_ENDIO_METADATA);
945 		if (ret)
946 			goto out_w_error;
947 		ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
948 				    mirror_num, 0);
949 	} else if (!async) {
950 		ret = btree_csum_one_bio(bio);
951 		if (ret)
952 			goto out_w_error;
953 		ret = btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
954 				    mirror_num, 0);
955 	} else {
956 		/*
957 		 * kthread helpers are used to submit writes so that
958 		 * checksumming can happen in parallel across all CPUs
959 		 */
960 		ret = btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
961 					  inode, rw, bio, mirror_num, 0,
962 					  bio_offset,
963 					  __btree_submit_bio_start,
964 					  __btree_submit_bio_done);
965 	}
966 
967 	if (ret) {
968 out_w_error:
969 		bio_endio(bio, ret);
970 	}
971 	return ret;
972 }
973 
974 #ifdef CONFIG_MIGRATION
975 static int btree_migratepage(struct address_space *mapping,
976 			struct page *newpage, struct page *page,
977 			enum migrate_mode mode)
978 {
979 	/*
980 	 * we can't safely write a btree page from here,
981 	 * we haven't done the locking hook
982 	 */
983 	if (PageDirty(page))
984 		return -EAGAIN;
985 	/*
986 	 * Buffers may be managed in a filesystem specific way.
987 	 * We must have no buffers or drop them.
988 	 */
989 	if (page_has_private(page) &&
990 	    !try_to_release_page(page, GFP_KERNEL))
991 		return -EAGAIN;
992 	return migrate_page(mapping, newpage, page, mode);
993 }
994 #endif
995 
996 
997 static int btree_writepages(struct address_space *mapping,
998 			    struct writeback_control *wbc)
999 {
1000 	struct btrfs_fs_info *fs_info;
1001 	int ret;
1002 
1003 	if (wbc->sync_mode == WB_SYNC_NONE) {
1004 
1005 		if (wbc->for_kupdate)
1006 			return 0;
1007 
1008 		fs_info = BTRFS_I(mapping->host)->root->fs_info;
1009 		/* this is a bit racy, but that's ok */
1010 		ret = percpu_counter_compare(&fs_info->dirty_metadata_bytes,
1011 					     BTRFS_DIRTY_METADATA_THRESH);
1012 		if (ret < 0)
1013 			return 0;
1014 	}
1015 	return btree_write_cache_pages(mapping, wbc);
1016 }
1017 
1018 static int btree_readpage(struct file *file, struct page *page)
1019 {
1020 	struct extent_io_tree *tree;
1021 	tree = &BTRFS_I(page->mapping->host)->io_tree;
1022 	return extent_read_full_page(tree, page, btree_get_extent, 0);
1023 }
1024 
1025 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
1026 {
1027 	if (PageWriteback(page) || PageDirty(page))
1028 		return 0;
1029 
1030 	return try_release_extent_buffer(page);
1031 }
1032 
1033 static void btree_invalidatepage(struct page *page, unsigned int offset,
1034 				 unsigned int length)
1035 {
1036 	struct extent_io_tree *tree;
1037 	tree = &BTRFS_I(page->mapping->host)->io_tree;
1038 	extent_invalidatepage(tree, page, offset);
1039 	btree_releasepage(page, GFP_NOFS);
1040 	if (PagePrivate(page)) {
1041 		btrfs_warn(BTRFS_I(page->mapping->host)->root->fs_info,
1042 			   "page private not zero on page %llu",
1043 			   (unsigned long long)page_offset(page));
1044 		ClearPagePrivate(page);
1045 		set_page_private(page, 0);
1046 		page_cache_release(page);
1047 	}
1048 }
1049 
1050 static int btree_set_page_dirty(struct page *page)
1051 {
1052 #ifdef DEBUG
1053 	struct extent_buffer *eb;
1054 
1055 	BUG_ON(!PagePrivate(page));
1056 	eb = (struct extent_buffer *)page->private;
1057 	BUG_ON(!eb);
1058 	BUG_ON(!test_bit(EXTENT_BUFFER_DIRTY, &eb->bflags));
1059 	BUG_ON(!atomic_read(&eb->refs));
1060 	btrfs_assert_tree_locked(eb);
1061 #endif
1062 	return __set_page_dirty_nobuffers(page);
1063 }
1064 
1065 static const struct address_space_operations btree_aops = {
1066 	.readpage	= btree_readpage,
1067 	.writepages	= btree_writepages,
1068 	.releasepage	= btree_releasepage,
1069 	.invalidatepage = btree_invalidatepage,
1070 #ifdef CONFIG_MIGRATION
1071 	.migratepage	= btree_migratepage,
1072 #endif
1073 	.set_page_dirty = btree_set_page_dirty,
1074 };
1075 
1076 void readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize)
1077 {
1078 	struct extent_buffer *buf = NULL;
1079 	struct inode *btree_inode = root->fs_info->btree_inode;
1080 
1081 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1082 	if (!buf)
1083 		return;
1084 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1085 				 buf, 0, WAIT_NONE, btree_get_extent, 0);
1086 	free_extent_buffer(buf);
1087 }
1088 
1089 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1090 			 int mirror_num, struct extent_buffer **eb)
1091 {
1092 	struct extent_buffer *buf = NULL;
1093 	struct inode *btree_inode = root->fs_info->btree_inode;
1094 	struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1095 	int ret;
1096 
1097 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1098 	if (!buf)
1099 		return 0;
1100 
1101 	set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1102 
1103 	ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1104 				       btree_get_extent, mirror_num);
1105 	if (ret) {
1106 		free_extent_buffer(buf);
1107 		return ret;
1108 	}
1109 
1110 	if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1111 		free_extent_buffer(buf);
1112 		return -EIO;
1113 	} else if (extent_buffer_uptodate(buf)) {
1114 		*eb = buf;
1115 	} else {
1116 		free_extent_buffer(buf);
1117 	}
1118 	return 0;
1119 }
1120 
1121 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1122 					    u64 bytenr)
1123 {
1124 	return find_extent_buffer(root->fs_info, bytenr);
1125 }
1126 
1127 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1128 						 u64 bytenr, u32 blocksize)
1129 {
1130 	if (btrfs_test_is_dummy_root(root))
1131 		return alloc_test_extent_buffer(root->fs_info, bytenr,
1132 						blocksize);
1133 	return alloc_extent_buffer(root->fs_info, bytenr, blocksize);
1134 }
1135 
1136 
1137 int btrfs_write_tree_block(struct extent_buffer *buf)
1138 {
1139 	return filemap_fdatawrite_range(buf->pages[0]->mapping, buf->start,
1140 					buf->start + buf->len - 1);
1141 }
1142 
1143 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1144 {
1145 	return filemap_fdatawait_range(buf->pages[0]->mapping,
1146 				       buf->start, buf->start + buf->len - 1);
1147 }
1148 
1149 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1150 				      u64 parent_transid)
1151 {
1152 	struct extent_buffer *buf = NULL;
1153 	int ret;
1154 
1155 	buf = btrfs_find_create_tree_block(root, bytenr, root->nodesize);
1156 	if (!buf)
1157 		return NULL;
1158 
1159 	ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1160 	if (ret) {
1161 		free_extent_buffer(buf);
1162 		return NULL;
1163 	}
1164 	return buf;
1165 
1166 }
1167 
1168 void clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1169 		      struct extent_buffer *buf)
1170 {
1171 	struct btrfs_fs_info *fs_info = root->fs_info;
1172 
1173 	if (btrfs_header_generation(buf) ==
1174 	    fs_info->running_transaction->transid) {
1175 		btrfs_assert_tree_locked(buf);
1176 
1177 		if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1178 			__percpu_counter_add(&fs_info->dirty_metadata_bytes,
1179 					     -buf->len,
1180 					     fs_info->dirty_metadata_batch);
1181 			/* ugh, clear_extent_buffer_dirty needs to lock the page */
1182 			btrfs_set_lock_blocking(buf);
1183 			clear_extent_buffer_dirty(buf);
1184 		}
1185 	}
1186 }
1187 
1188 static struct btrfs_subvolume_writers *btrfs_alloc_subvolume_writers(void)
1189 {
1190 	struct btrfs_subvolume_writers *writers;
1191 	int ret;
1192 
1193 	writers = kmalloc(sizeof(*writers), GFP_NOFS);
1194 	if (!writers)
1195 		return ERR_PTR(-ENOMEM);
1196 
1197 	ret = percpu_counter_init(&writers->counter, 0, GFP_KERNEL);
1198 	if (ret < 0) {
1199 		kfree(writers);
1200 		return ERR_PTR(ret);
1201 	}
1202 
1203 	init_waitqueue_head(&writers->wait);
1204 	return writers;
1205 }
1206 
1207 static void
1208 btrfs_free_subvolume_writers(struct btrfs_subvolume_writers *writers)
1209 {
1210 	percpu_counter_destroy(&writers->counter);
1211 	kfree(writers);
1212 }
1213 
1214 static void __setup_root(u32 nodesize, u32 sectorsize, u32 stripesize,
1215 			 struct btrfs_root *root, struct btrfs_fs_info *fs_info,
1216 			 u64 objectid)
1217 {
1218 	root->node = NULL;
1219 	root->commit_root = NULL;
1220 	root->sectorsize = sectorsize;
1221 	root->nodesize = nodesize;
1222 	root->stripesize = stripesize;
1223 	root->state = 0;
1224 	root->orphan_cleanup_state = 0;
1225 
1226 	root->objectid = objectid;
1227 	root->last_trans = 0;
1228 	root->highest_objectid = 0;
1229 	root->nr_delalloc_inodes = 0;
1230 	root->nr_ordered_extents = 0;
1231 	root->name = NULL;
1232 	root->inode_tree = RB_ROOT;
1233 	INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1234 	root->block_rsv = NULL;
1235 	root->orphan_block_rsv = NULL;
1236 
1237 	INIT_LIST_HEAD(&root->dirty_list);
1238 	INIT_LIST_HEAD(&root->root_list);
1239 	INIT_LIST_HEAD(&root->delalloc_inodes);
1240 	INIT_LIST_HEAD(&root->delalloc_root);
1241 	INIT_LIST_HEAD(&root->ordered_extents);
1242 	INIT_LIST_HEAD(&root->ordered_root);
1243 	INIT_LIST_HEAD(&root->logged_list[0]);
1244 	INIT_LIST_HEAD(&root->logged_list[1]);
1245 	spin_lock_init(&root->orphan_lock);
1246 	spin_lock_init(&root->inode_lock);
1247 	spin_lock_init(&root->delalloc_lock);
1248 	spin_lock_init(&root->ordered_extent_lock);
1249 	spin_lock_init(&root->accounting_lock);
1250 	spin_lock_init(&root->log_extents_lock[0]);
1251 	spin_lock_init(&root->log_extents_lock[1]);
1252 	mutex_init(&root->objectid_mutex);
1253 	mutex_init(&root->log_mutex);
1254 	mutex_init(&root->ordered_extent_mutex);
1255 	mutex_init(&root->delalloc_mutex);
1256 	init_waitqueue_head(&root->log_writer_wait);
1257 	init_waitqueue_head(&root->log_commit_wait[0]);
1258 	init_waitqueue_head(&root->log_commit_wait[1]);
1259 	INIT_LIST_HEAD(&root->log_ctxs[0]);
1260 	INIT_LIST_HEAD(&root->log_ctxs[1]);
1261 	atomic_set(&root->log_commit[0], 0);
1262 	atomic_set(&root->log_commit[1], 0);
1263 	atomic_set(&root->log_writers, 0);
1264 	atomic_set(&root->log_batch, 0);
1265 	atomic_set(&root->orphan_inodes, 0);
1266 	atomic_set(&root->refs, 1);
1267 	atomic_set(&root->will_be_snapshoted, 0);
1268 	root->log_transid = 0;
1269 	root->log_transid_committed = -1;
1270 	root->last_log_commit = 0;
1271 	if (fs_info)
1272 		extent_io_tree_init(&root->dirty_log_pages,
1273 				     fs_info->btree_inode->i_mapping);
1274 
1275 	memset(&root->root_key, 0, sizeof(root->root_key));
1276 	memset(&root->root_item, 0, sizeof(root->root_item));
1277 	memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1278 	memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1279 	if (fs_info)
1280 		root->defrag_trans_start = fs_info->generation;
1281 	else
1282 		root->defrag_trans_start = 0;
1283 	init_completion(&root->kobj_unregister);
1284 	root->root_key.objectid = objectid;
1285 	root->anon_dev = 0;
1286 
1287 	spin_lock_init(&root->root_item_lock);
1288 }
1289 
1290 static struct btrfs_root *btrfs_alloc_root(struct btrfs_fs_info *fs_info)
1291 {
1292 	struct btrfs_root *root = kzalloc(sizeof(*root), GFP_NOFS);
1293 	if (root)
1294 		root->fs_info = fs_info;
1295 	return root;
1296 }
1297 
1298 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
1299 /* Should only be used by the testing infrastructure */
1300 struct btrfs_root *btrfs_alloc_dummy_root(void)
1301 {
1302 	struct btrfs_root *root;
1303 
1304 	root = btrfs_alloc_root(NULL);
1305 	if (!root)
1306 		return ERR_PTR(-ENOMEM);
1307 	__setup_root(4096, 4096, 4096, root, NULL, 1);
1308 	set_bit(BTRFS_ROOT_DUMMY_ROOT, &root->state);
1309 	root->alloc_bytenr = 0;
1310 
1311 	return root;
1312 }
1313 #endif
1314 
1315 struct btrfs_root *btrfs_create_tree(struct btrfs_trans_handle *trans,
1316 				     struct btrfs_fs_info *fs_info,
1317 				     u64 objectid)
1318 {
1319 	struct extent_buffer *leaf;
1320 	struct btrfs_root *tree_root = fs_info->tree_root;
1321 	struct btrfs_root *root;
1322 	struct btrfs_key key;
1323 	int ret = 0;
1324 	uuid_le uuid;
1325 
1326 	root = btrfs_alloc_root(fs_info);
1327 	if (!root)
1328 		return ERR_PTR(-ENOMEM);
1329 
1330 	__setup_root(tree_root->nodesize, tree_root->sectorsize,
1331 		tree_root->stripesize, root, fs_info, objectid);
1332 	root->root_key.objectid = objectid;
1333 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1334 	root->root_key.offset = 0;
1335 
1336 	leaf = btrfs_alloc_tree_block(trans, root, 0, objectid, NULL, 0, 0, 0);
1337 	if (IS_ERR(leaf)) {
1338 		ret = PTR_ERR(leaf);
1339 		leaf = NULL;
1340 		goto fail;
1341 	}
1342 
1343 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1344 	btrfs_set_header_bytenr(leaf, leaf->start);
1345 	btrfs_set_header_generation(leaf, trans->transid);
1346 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1347 	btrfs_set_header_owner(leaf, objectid);
1348 	root->node = leaf;
1349 
1350 	write_extent_buffer(leaf, fs_info->fsid, btrfs_header_fsid(),
1351 			    BTRFS_FSID_SIZE);
1352 	write_extent_buffer(leaf, fs_info->chunk_tree_uuid,
1353 			    btrfs_header_chunk_tree_uuid(leaf),
1354 			    BTRFS_UUID_SIZE);
1355 	btrfs_mark_buffer_dirty(leaf);
1356 
1357 	root->commit_root = btrfs_root_node(root);
1358 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &root->state);
1359 
1360 	root->root_item.flags = 0;
1361 	root->root_item.byte_limit = 0;
1362 	btrfs_set_root_bytenr(&root->root_item, leaf->start);
1363 	btrfs_set_root_generation(&root->root_item, trans->transid);
1364 	btrfs_set_root_level(&root->root_item, 0);
1365 	btrfs_set_root_refs(&root->root_item, 1);
1366 	btrfs_set_root_used(&root->root_item, leaf->len);
1367 	btrfs_set_root_last_snapshot(&root->root_item, 0);
1368 	btrfs_set_root_dirid(&root->root_item, 0);
1369 	uuid_le_gen(&uuid);
1370 	memcpy(root->root_item.uuid, uuid.b, BTRFS_UUID_SIZE);
1371 	root->root_item.drop_level = 0;
1372 
1373 	key.objectid = objectid;
1374 	key.type = BTRFS_ROOT_ITEM_KEY;
1375 	key.offset = 0;
1376 	ret = btrfs_insert_root(trans, tree_root, &key, &root->root_item);
1377 	if (ret)
1378 		goto fail;
1379 
1380 	btrfs_tree_unlock(leaf);
1381 
1382 	return root;
1383 
1384 fail:
1385 	if (leaf) {
1386 		btrfs_tree_unlock(leaf);
1387 		free_extent_buffer(root->commit_root);
1388 		free_extent_buffer(leaf);
1389 	}
1390 	kfree(root);
1391 
1392 	return ERR_PTR(ret);
1393 }
1394 
1395 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1396 					 struct btrfs_fs_info *fs_info)
1397 {
1398 	struct btrfs_root *root;
1399 	struct btrfs_root *tree_root = fs_info->tree_root;
1400 	struct extent_buffer *leaf;
1401 
1402 	root = btrfs_alloc_root(fs_info);
1403 	if (!root)
1404 		return ERR_PTR(-ENOMEM);
1405 
1406 	__setup_root(tree_root->nodesize, tree_root->sectorsize,
1407 		     tree_root->stripesize, root, fs_info,
1408 		     BTRFS_TREE_LOG_OBJECTID);
1409 
1410 	root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1411 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1412 	root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1413 
1414 	/*
1415 	 * DON'T set REF_COWS for log trees
1416 	 *
1417 	 * log trees do not get reference counted because they go away
1418 	 * before a real commit is actually done.  They do store pointers
1419 	 * to file data extents, and those reference counts still get
1420 	 * updated (along with back refs to the log tree).
1421 	 */
1422 
1423 	leaf = btrfs_alloc_tree_block(trans, root, 0, BTRFS_TREE_LOG_OBJECTID,
1424 			NULL, 0, 0, 0);
1425 	if (IS_ERR(leaf)) {
1426 		kfree(root);
1427 		return ERR_CAST(leaf);
1428 	}
1429 
1430 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1431 	btrfs_set_header_bytenr(leaf, leaf->start);
1432 	btrfs_set_header_generation(leaf, trans->transid);
1433 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1434 	btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1435 	root->node = leaf;
1436 
1437 	write_extent_buffer(root->node, root->fs_info->fsid,
1438 			    btrfs_header_fsid(), BTRFS_FSID_SIZE);
1439 	btrfs_mark_buffer_dirty(root->node);
1440 	btrfs_tree_unlock(root->node);
1441 	return root;
1442 }
1443 
1444 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1445 			     struct btrfs_fs_info *fs_info)
1446 {
1447 	struct btrfs_root *log_root;
1448 
1449 	log_root = alloc_log_tree(trans, fs_info);
1450 	if (IS_ERR(log_root))
1451 		return PTR_ERR(log_root);
1452 	WARN_ON(fs_info->log_root_tree);
1453 	fs_info->log_root_tree = log_root;
1454 	return 0;
1455 }
1456 
1457 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1458 		       struct btrfs_root *root)
1459 {
1460 	struct btrfs_root *log_root;
1461 	struct btrfs_inode_item *inode_item;
1462 
1463 	log_root = alloc_log_tree(trans, root->fs_info);
1464 	if (IS_ERR(log_root))
1465 		return PTR_ERR(log_root);
1466 
1467 	log_root->last_trans = trans->transid;
1468 	log_root->root_key.offset = root->root_key.objectid;
1469 
1470 	inode_item = &log_root->root_item.inode;
1471 	btrfs_set_stack_inode_generation(inode_item, 1);
1472 	btrfs_set_stack_inode_size(inode_item, 3);
1473 	btrfs_set_stack_inode_nlink(inode_item, 1);
1474 	btrfs_set_stack_inode_nbytes(inode_item, root->nodesize);
1475 	btrfs_set_stack_inode_mode(inode_item, S_IFDIR | 0755);
1476 
1477 	btrfs_set_root_node(&log_root->root_item, log_root->node);
1478 
1479 	WARN_ON(root->log_root);
1480 	root->log_root = log_root;
1481 	root->log_transid = 0;
1482 	root->log_transid_committed = -1;
1483 	root->last_log_commit = 0;
1484 	return 0;
1485 }
1486 
1487 static struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
1488 					       struct btrfs_key *key)
1489 {
1490 	struct btrfs_root *root;
1491 	struct btrfs_fs_info *fs_info = tree_root->fs_info;
1492 	struct btrfs_path *path;
1493 	u64 generation;
1494 	int ret;
1495 
1496 	path = btrfs_alloc_path();
1497 	if (!path)
1498 		return ERR_PTR(-ENOMEM);
1499 
1500 	root = btrfs_alloc_root(fs_info);
1501 	if (!root) {
1502 		ret = -ENOMEM;
1503 		goto alloc_fail;
1504 	}
1505 
1506 	__setup_root(tree_root->nodesize, tree_root->sectorsize,
1507 		tree_root->stripesize, root, fs_info, key->objectid);
1508 
1509 	ret = btrfs_find_root(tree_root, key, path,
1510 			      &root->root_item, &root->root_key);
1511 	if (ret) {
1512 		if (ret > 0)
1513 			ret = -ENOENT;
1514 		goto find_fail;
1515 	}
1516 
1517 	generation = btrfs_root_generation(&root->root_item);
1518 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1519 				     generation);
1520 	if (!root->node) {
1521 		ret = -ENOMEM;
1522 		goto find_fail;
1523 	} else if (!btrfs_buffer_uptodate(root->node, generation, 0)) {
1524 		ret = -EIO;
1525 		goto read_fail;
1526 	}
1527 	root->commit_root = btrfs_root_node(root);
1528 out:
1529 	btrfs_free_path(path);
1530 	return root;
1531 
1532 read_fail:
1533 	free_extent_buffer(root->node);
1534 find_fail:
1535 	kfree(root);
1536 alloc_fail:
1537 	root = ERR_PTR(ret);
1538 	goto out;
1539 }
1540 
1541 struct btrfs_root *btrfs_read_fs_root(struct btrfs_root *tree_root,
1542 				      struct btrfs_key *location)
1543 {
1544 	struct btrfs_root *root;
1545 
1546 	root = btrfs_read_tree_root(tree_root, location);
1547 	if (IS_ERR(root))
1548 		return root;
1549 
1550 	if (root->root_key.objectid != BTRFS_TREE_LOG_OBJECTID) {
1551 		set_bit(BTRFS_ROOT_REF_COWS, &root->state);
1552 		btrfs_check_and_init_root_item(&root->root_item);
1553 	}
1554 
1555 	return root;
1556 }
1557 
1558 int btrfs_init_fs_root(struct btrfs_root *root)
1559 {
1560 	int ret;
1561 	struct btrfs_subvolume_writers *writers;
1562 
1563 	root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1564 	root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1565 					GFP_NOFS);
1566 	if (!root->free_ino_pinned || !root->free_ino_ctl) {
1567 		ret = -ENOMEM;
1568 		goto fail;
1569 	}
1570 
1571 	writers = btrfs_alloc_subvolume_writers();
1572 	if (IS_ERR(writers)) {
1573 		ret = PTR_ERR(writers);
1574 		goto fail;
1575 	}
1576 	root->subv_writers = writers;
1577 
1578 	btrfs_init_free_ino_ctl(root);
1579 	spin_lock_init(&root->ino_cache_lock);
1580 	init_waitqueue_head(&root->ino_cache_wait);
1581 
1582 	ret = get_anon_bdev(&root->anon_dev);
1583 	if (ret)
1584 		goto free_writers;
1585 	return 0;
1586 
1587 free_writers:
1588 	btrfs_free_subvolume_writers(root->subv_writers);
1589 fail:
1590 	kfree(root->free_ino_ctl);
1591 	kfree(root->free_ino_pinned);
1592 	return ret;
1593 }
1594 
1595 static struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1596 					       u64 root_id)
1597 {
1598 	struct btrfs_root *root;
1599 
1600 	spin_lock(&fs_info->fs_roots_radix_lock);
1601 	root = radix_tree_lookup(&fs_info->fs_roots_radix,
1602 				 (unsigned long)root_id);
1603 	spin_unlock(&fs_info->fs_roots_radix_lock);
1604 	return root;
1605 }
1606 
1607 int btrfs_insert_fs_root(struct btrfs_fs_info *fs_info,
1608 			 struct btrfs_root *root)
1609 {
1610 	int ret;
1611 
1612 	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1613 	if (ret)
1614 		return ret;
1615 
1616 	spin_lock(&fs_info->fs_roots_radix_lock);
1617 	ret = radix_tree_insert(&fs_info->fs_roots_radix,
1618 				(unsigned long)root->root_key.objectid,
1619 				root);
1620 	if (ret == 0)
1621 		set_bit(BTRFS_ROOT_IN_RADIX, &root->state);
1622 	spin_unlock(&fs_info->fs_roots_radix_lock);
1623 	radix_tree_preload_end();
1624 
1625 	return ret;
1626 }
1627 
1628 struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
1629 				     struct btrfs_key *location,
1630 				     bool check_ref)
1631 {
1632 	struct btrfs_root *root;
1633 	int ret;
1634 
1635 	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1636 		return fs_info->tree_root;
1637 	if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1638 		return fs_info->extent_root;
1639 	if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1640 		return fs_info->chunk_root;
1641 	if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1642 		return fs_info->dev_root;
1643 	if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1644 		return fs_info->csum_root;
1645 	if (location->objectid == BTRFS_QUOTA_TREE_OBJECTID)
1646 		return fs_info->quota_root ? fs_info->quota_root :
1647 					     ERR_PTR(-ENOENT);
1648 	if (location->objectid == BTRFS_UUID_TREE_OBJECTID)
1649 		return fs_info->uuid_root ? fs_info->uuid_root :
1650 					    ERR_PTR(-ENOENT);
1651 again:
1652 	root = btrfs_lookup_fs_root(fs_info, location->objectid);
1653 	if (root) {
1654 		if (check_ref && btrfs_root_refs(&root->root_item) == 0)
1655 			return ERR_PTR(-ENOENT);
1656 		return root;
1657 	}
1658 
1659 	root = btrfs_read_fs_root(fs_info->tree_root, location);
1660 	if (IS_ERR(root))
1661 		return root;
1662 
1663 	if (check_ref && btrfs_root_refs(&root->root_item) == 0) {
1664 		ret = -ENOENT;
1665 		goto fail;
1666 	}
1667 
1668 	ret = btrfs_init_fs_root(root);
1669 	if (ret)
1670 		goto fail;
1671 
1672 	ret = btrfs_find_item(fs_info->tree_root, NULL, BTRFS_ORPHAN_OBJECTID,
1673 			location->objectid, BTRFS_ORPHAN_ITEM_KEY, NULL);
1674 	if (ret < 0)
1675 		goto fail;
1676 	if (ret == 0)
1677 		set_bit(BTRFS_ROOT_ORPHAN_ITEM_INSERTED, &root->state);
1678 
1679 	ret = btrfs_insert_fs_root(fs_info, root);
1680 	if (ret) {
1681 		if (ret == -EEXIST) {
1682 			free_fs_root(root);
1683 			goto again;
1684 		}
1685 		goto fail;
1686 	}
1687 	return root;
1688 fail:
1689 	free_fs_root(root);
1690 	return ERR_PTR(ret);
1691 }
1692 
1693 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1694 {
1695 	struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1696 	int ret = 0;
1697 	struct btrfs_device *device;
1698 	struct backing_dev_info *bdi;
1699 
1700 	rcu_read_lock();
1701 	list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1702 		if (!device->bdev)
1703 			continue;
1704 		bdi = blk_get_backing_dev_info(device->bdev);
1705 		if (bdi_congested(bdi, bdi_bits)) {
1706 			ret = 1;
1707 			break;
1708 		}
1709 	}
1710 	rcu_read_unlock();
1711 	return ret;
1712 }
1713 
1714 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1715 {
1716 	int err;
1717 
1718 	bdi->capabilities = BDI_CAP_MAP_COPY;
1719 	err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1720 	if (err)
1721 		return err;
1722 
1723 	bdi->ra_pages	= default_backing_dev_info.ra_pages;
1724 	bdi->congested_fn	= btrfs_congested_fn;
1725 	bdi->congested_data	= info;
1726 	return 0;
1727 }
1728 
1729 /*
1730  * called by the kthread helper functions to finally call the bio end_io
1731  * functions.  This is where read checksum verification actually happens
1732  */
1733 static void end_workqueue_fn(struct btrfs_work *work)
1734 {
1735 	struct bio *bio;
1736 	struct btrfs_end_io_wq *end_io_wq;
1737 	int error;
1738 
1739 	end_io_wq = container_of(work, struct btrfs_end_io_wq, work);
1740 	bio = end_io_wq->bio;
1741 
1742 	error = end_io_wq->error;
1743 	bio->bi_private = end_io_wq->private;
1744 	bio->bi_end_io = end_io_wq->end_io;
1745 	kmem_cache_free(btrfs_end_io_wq_cache, end_io_wq);
1746 	bio_endio_nodec(bio, error);
1747 }
1748 
1749 static int cleaner_kthread(void *arg)
1750 {
1751 	struct btrfs_root *root = arg;
1752 	int again;
1753 
1754 	do {
1755 		again = 0;
1756 
1757 		/* Make the cleaner go to sleep early. */
1758 		if (btrfs_need_cleaner_sleep(root))
1759 			goto sleep;
1760 
1761 		if (!mutex_trylock(&root->fs_info->cleaner_mutex))
1762 			goto sleep;
1763 
1764 		/*
1765 		 * Avoid the problem that we change the status of the fs
1766 		 * during the above check and trylock.
1767 		 */
1768 		if (btrfs_need_cleaner_sleep(root)) {
1769 			mutex_unlock(&root->fs_info->cleaner_mutex);
1770 			goto sleep;
1771 		}
1772 
1773 		btrfs_run_delayed_iputs(root);
1774 		btrfs_delete_unused_bgs(root->fs_info);
1775 		again = btrfs_clean_one_deleted_snapshot(root);
1776 		mutex_unlock(&root->fs_info->cleaner_mutex);
1777 
1778 		/*
1779 		 * The defragger has dealt with the R/O remount and umount,
1780 		 * needn't do anything special here.
1781 		 */
1782 		btrfs_run_defrag_inodes(root->fs_info);
1783 sleep:
1784 		if (!try_to_freeze() && !again) {
1785 			set_current_state(TASK_INTERRUPTIBLE);
1786 			if (!kthread_should_stop())
1787 				schedule();
1788 			__set_current_state(TASK_RUNNING);
1789 		}
1790 	} while (!kthread_should_stop());
1791 	return 0;
1792 }
1793 
1794 static int transaction_kthread(void *arg)
1795 {
1796 	struct btrfs_root *root = arg;
1797 	struct btrfs_trans_handle *trans;
1798 	struct btrfs_transaction *cur;
1799 	u64 transid;
1800 	unsigned long now;
1801 	unsigned long delay;
1802 	bool cannot_commit;
1803 
1804 	do {
1805 		cannot_commit = false;
1806 		delay = HZ * root->fs_info->commit_interval;
1807 		mutex_lock(&root->fs_info->transaction_kthread_mutex);
1808 
1809 		spin_lock(&root->fs_info->trans_lock);
1810 		cur = root->fs_info->running_transaction;
1811 		if (!cur) {
1812 			spin_unlock(&root->fs_info->trans_lock);
1813 			goto sleep;
1814 		}
1815 
1816 		now = get_seconds();
1817 		if (cur->state < TRANS_STATE_BLOCKED &&
1818 		    (now < cur->start_time ||
1819 		     now - cur->start_time < root->fs_info->commit_interval)) {
1820 			spin_unlock(&root->fs_info->trans_lock);
1821 			delay = HZ * 5;
1822 			goto sleep;
1823 		}
1824 		transid = cur->transid;
1825 		spin_unlock(&root->fs_info->trans_lock);
1826 
1827 		/* If the file system is aborted, this will always fail. */
1828 		trans = btrfs_attach_transaction(root);
1829 		if (IS_ERR(trans)) {
1830 			if (PTR_ERR(trans) != -ENOENT)
1831 				cannot_commit = true;
1832 			goto sleep;
1833 		}
1834 		if (transid == trans->transid) {
1835 			btrfs_commit_transaction(trans, root);
1836 		} else {
1837 			btrfs_end_transaction(trans, root);
1838 		}
1839 sleep:
1840 		wake_up_process(root->fs_info->cleaner_kthread);
1841 		mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1842 
1843 		if (unlikely(test_bit(BTRFS_FS_STATE_ERROR,
1844 				      &root->fs_info->fs_state)))
1845 			btrfs_cleanup_transaction(root);
1846 		if (!try_to_freeze()) {
1847 			set_current_state(TASK_INTERRUPTIBLE);
1848 			if (!kthread_should_stop() &&
1849 			    (!btrfs_transaction_blocked(root->fs_info) ||
1850 			     cannot_commit))
1851 				schedule_timeout(delay);
1852 			__set_current_state(TASK_RUNNING);
1853 		}
1854 	} while (!kthread_should_stop());
1855 	return 0;
1856 }
1857 
1858 /*
1859  * this will find the highest generation in the array of
1860  * root backups.  The index of the highest array is returned,
1861  * or -1 if we can't find anything.
1862  *
1863  * We check to make sure the array is valid by comparing the
1864  * generation of the latest  root in the array with the generation
1865  * in the super block.  If they don't match we pitch it.
1866  */
1867 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1868 {
1869 	u64 cur;
1870 	int newest_index = -1;
1871 	struct btrfs_root_backup *root_backup;
1872 	int i;
1873 
1874 	for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1875 		root_backup = info->super_copy->super_roots + i;
1876 		cur = btrfs_backup_tree_root_gen(root_backup);
1877 		if (cur == newest_gen)
1878 			newest_index = i;
1879 	}
1880 
1881 	/* check to see if we actually wrapped around */
1882 	if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1883 		root_backup = info->super_copy->super_roots;
1884 		cur = btrfs_backup_tree_root_gen(root_backup);
1885 		if (cur == newest_gen)
1886 			newest_index = 0;
1887 	}
1888 	return newest_index;
1889 }
1890 
1891 
1892 /*
1893  * find the oldest backup so we know where to store new entries
1894  * in the backup array.  This will set the backup_root_index
1895  * field in the fs_info struct
1896  */
1897 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1898 				     u64 newest_gen)
1899 {
1900 	int newest_index = -1;
1901 
1902 	newest_index = find_newest_super_backup(info, newest_gen);
1903 	/* if there was garbage in there, just move along */
1904 	if (newest_index == -1) {
1905 		info->backup_root_index = 0;
1906 	} else {
1907 		info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1908 	}
1909 }
1910 
1911 /*
1912  * copy all the root pointers into the super backup array.
1913  * this will bump the backup pointer by one when it is
1914  * done
1915  */
1916 static void backup_super_roots(struct btrfs_fs_info *info)
1917 {
1918 	int next_backup;
1919 	struct btrfs_root_backup *root_backup;
1920 	int last_backup;
1921 
1922 	next_backup = info->backup_root_index;
1923 	last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1924 		BTRFS_NUM_BACKUP_ROOTS;
1925 
1926 	/*
1927 	 * just overwrite the last backup if we're at the same generation
1928 	 * this happens only at umount
1929 	 */
1930 	root_backup = info->super_for_commit->super_roots + last_backup;
1931 	if (btrfs_backup_tree_root_gen(root_backup) ==
1932 	    btrfs_header_generation(info->tree_root->node))
1933 		next_backup = last_backup;
1934 
1935 	root_backup = info->super_for_commit->super_roots + next_backup;
1936 
1937 	/*
1938 	 * make sure all of our padding and empty slots get zero filled
1939 	 * regardless of which ones we use today
1940 	 */
1941 	memset(root_backup, 0, sizeof(*root_backup));
1942 
1943 	info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1944 
1945 	btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1946 	btrfs_set_backup_tree_root_gen(root_backup,
1947 			       btrfs_header_generation(info->tree_root->node));
1948 
1949 	btrfs_set_backup_tree_root_level(root_backup,
1950 			       btrfs_header_level(info->tree_root->node));
1951 
1952 	btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1953 	btrfs_set_backup_chunk_root_gen(root_backup,
1954 			       btrfs_header_generation(info->chunk_root->node));
1955 	btrfs_set_backup_chunk_root_level(root_backup,
1956 			       btrfs_header_level(info->chunk_root->node));
1957 
1958 	btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1959 	btrfs_set_backup_extent_root_gen(root_backup,
1960 			       btrfs_header_generation(info->extent_root->node));
1961 	btrfs_set_backup_extent_root_level(root_backup,
1962 			       btrfs_header_level(info->extent_root->node));
1963 
1964 	/*
1965 	 * we might commit during log recovery, which happens before we set
1966 	 * the fs_root.  Make sure it is valid before we fill it in.
1967 	 */
1968 	if (info->fs_root && info->fs_root->node) {
1969 		btrfs_set_backup_fs_root(root_backup,
1970 					 info->fs_root->node->start);
1971 		btrfs_set_backup_fs_root_gen(root_backup,
1972 			       btrfs_header_generation(info->fs_root->node));
1973 		btrfs_set_backup_fs_root_level(root_backup,
1974 			       btrfs_header_level(info->fs_root->node));
1975 	}
1976 
1977 	btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1978 	btrfs_set_backup_dev_root_gen(root_backup,
1979 			       btrfs_header_generation(info->dev_root->node));
1980 	btrfs_set_backup_dev_root_level(root_backup,
1981 				       btrfs_header_level(info->dev_root->node));
1982 
1983 	btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1984 	btrfs_set_backup_csum_root_gen(root_backup,
1985 			       btrfs_header_generation(info->csum_root->node));
1986 	btrfs_set_backup_csum_root_level(root_backup,
1987 			       btrfs_header_level(info->csum_root->node));
1988 
1989 	btrfs_set_backup_total_bytes(root_backup,
1990 			     btrfs_super_total_bytes(info->super_copy));
1991 	btrfs_set_backup_bytes_used(root_backup,
1992 			     btrfs_super_bytes_used(info->super_copy));
1993 	btrfs_set_backup_num_devices(root_backup,
1994 			     btrfs_super_num_devices(info->super_copy));
1995 
1996 	/*
1997 	 * if we don't copy this out to the super_copy, it won't get remembered
1998 	 * for the next commit
1999 	 */
2000 	memcpy(&info->super_copy->super_roots,
2001 	       &info->super_for_commit->super_roots,
2002 	       sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
2003 }
2004 
2005 /*
2006  * this copies info out of the root backup array and back into
2007  * the in-memory super block.  It is meant to help iterate through
2008  * the array, so you send it the number of backups you've already
2009  * tried and the last backup index you used.
2010  *
2011  * this returns -1 when it has tried all the backups
2012  */
2013 static noinline int next_root_backup(struct btrfs_fs_info *info,
2014 				     struct btrfs_super_block *super,
2015 				     int *num_backups_tried, int *backup_index)
2016 {
2017 	struct btrfs_root_backup *root_backup;
2018 	int newest = *backup_index;
2019 
2020 	if (*num_backups_tried == 0) {
2021 		u64 gen = btrfs_super_generation(super);
2022 
2023 		newest = find_newest_super_backup(info, gen);
2024 		if (newest == -1)
2025 			return -1;
2026 
2027 		*backup_index = newest;
2028 		*num_backups_tried = 1;
2029 	} else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
2030 		/* we've tried all the backups, all done */
2031 		return -1;
2032 	} else {
2033 		/* jump to the next oldest backup */
2034 		newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
2035 			BTRFS_NUM_BACKUP_ROOTS;
2036 		*backup_index = newest;
2037 		*num_backups_tried += 1;
2038 	}
2039 	root_backup = super->super_roots + newest;
2040 
2041 	btrfs_set_super_generation(super,
2042 				   btrfs_backup_tree_root_gen(root_backup));
2043 	btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
2044 	btrfs_set_super_root_level(super,
2045 				   btrfs_backup_tree_root_level(root_backup));
2046 	btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
2047 
2048 	/*
2049 	 * fixme: the total bytes and num_devices need to match or we should
2050 	 * need a fsck
2051 	 */
2052 	btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
2053 	btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
2054 	return 0;
2055 }
2056 
2057 /* helper to cleanup workers */
2058 static void btrfs_stop_all_workers(struct btrfs_fs_info *fs_info)
2059 {
2060 	btrfs_destroy_workqueue(fs_info->fixup_workers);
2061 	btrfs_destroy_workqueue(fs_info->delalloc_workers);
2062 	btrfs_destroy_workqueue(fs_info->workers);
2063 	btrfs_destroy_workqueue(fs_info->endio_workers);
2064 	btrfs_destroy_workqueue(fs_info->endio_meta_workers);
2065 	btrfs_destroy_workqueue(fs_info->endio_raid56_workers);
2066 	btrfs_destroy_workqueue(fs_info->endio_repair_workers);
2067 	btrfs_destroy_workqueue(fs_info->rmw_workers);
2068 	btrfs_destroy_workqueue(fs_info->endio_meta_write_workers);
2069 	btrfs_destroy_workqueue(fs_info->endio_write_workers);
2070 	btrfs_destroy_workqueue(fs_info->endio_freespace_worker);
2071 	btrfs_destroy_workqueue(fs_info->submit_workers);
2072 	btrfs_destroy_workqueue(fs_info->delayed_workers);
2073 	btrfs_destroy_workqueue(fs_info->caching_workers);
2074 	btrfs_destroy_workqueue(fs_info->readahead_workers);
2075 	btrfs_destroy_workqueue(fs_info->flush_workers);
2076 	btrfs_destroy_workqueue(fs_info->qgroup_rescan_workers);
2077 	btrfs_destroy_workqueue(fs_info->extent_workers);
2078 }
2079 
2080 static void free_root_extent_buffers(struct btrfs_root *root)
2081 {
2082 	if (root) {
2083 		free_extent_buffer(root->node);
2084 		free_extent_buffer(root->commit_root);
2085 		root->node = NULL;
2086 		root->commit_root = NULL;
2087 	}
2088 }
2089 
2090 /* helper to cleanup tree roots */
2091 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
2092 {
2093 	free_root_extent_buffers(info->tree_root);
2094 
2095 	free_root_extent_buffers(info->dev_root);
2096 	free_root_extent_buffers(info->extent_root);
2097 	free_root_extent_buffers(info->csum_root);
2098 	free_root_extent_buffers(info->quota_root);
2099 	free_root_extent_buffers(info->uuid_root);
2100 	if (chunk_root)
2101 		free_root_extent_buffers(info->chunk_root);
2102 }
2103 
2104 void btrfs_free_fs_roots(struct btrfs_fs_info *fs_info)
2105 {
2106 	int ret;
2107 	struct btrfs_root *gang[8];
2108 	int i;
2109 
2110 	while (!list_empty(&fs_info->dead_roots)) {
2111 		gang[0] = list_entry(fs_info->dead_roots.next,
2112 				     struct btrfs_root, root_list);
2113 		list_del(&gang[0]->root_list);
2114 
2115 		if (test_bit(BTRFS_ROOT_IN_RADIX, &gang[0]->state)) {
2116 			btrfs_drop_and_free_fs_root(fs_info, gang[0]);
2117 		} else {
2118 			free_extent_buffer(gang[0]->node);
2119 			free_extent_buffer(gang[0]->commit_root);
2120 			btrfs_put_fs_root(gang[0]);
2121 		}
2122 	}
2123 
2124 	while (1) {
2125 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2126 					     (void **)gang, 0,
2127 					     ARRAY_SIZE(gang));
2128 		if (!ret)
2129 			break;
2130 		for (i = 0; i < ret; i++)
2131 			btrfs_drop_and_free_fs_root(fs_info, gang[i]);
2132 	}
2133 
2134 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
2135 		btrfs_free_log_root_tree(NULL, fs_info);
2136 		btrfs_destroy_pinned_extent(fs_info->tree_root,
2137 					    fs_info->pinned_extents);
2138 	}
2139 }
2140 
2141 int open_ctree(struct super_block *sb,
2142 	       struct btrfs_fs_devices *fs_devices,
2143 	       char *options)
2144 {
2145 	u32 sectorsize;
2146 	u32 nodesize;
2147 	u32 stripesize;
2148 	u64 generation;
2149 	u64 features;
2150 	struct btrfs_key location;
2151 	struct buffer_head *bh;
2152 	struct btrfs_super_block *disk_super;
2153 	struct btrfs_fs_info *fs_info = btrfs_sb(sb);
2154 	struct btrfs_root *tree_root;
2155 	struct btrfs_root *extent_root;
2156 	struct btrfs_root *csum_root;
2157 	struct btrfs_root *chunk_root;
2158 	struct btrfs_root *dev_root;
2159 	struct btrfs_root *quota_root;
2160 	struct btrfs_root *uuid_root;
2161 	struct btrfs_root *log_tree_root;
2162 	int ret;
2163 	int err = -EINVAL;
2164 	int num_backups_tried = 0;
2165 	int backup_index = 0;
2166 	int max_active;
2167 	int flags = WQ_MEM_RECLAIM | WQ_FREEZABLE | WQ_UNBOUND;
2168 	bool create_uuid_tree;
2169 	bool check_uuid_tree;
2170 
2171 	tree_root = fs_info->tree_root = btrfs_alloc_root(fs_info);
2172 	chunk_root = fs_info->chunk_root = btrfs_alloc_root(fs_info);
2173 	if (!tree_root || !chunk_root) {
2174 		err = -ENOMEM;
2175 		goto fail;
2176 	}
2177 
2178 	ret = init_srcu_struct(&fs_info->subvol_srcu);
2179 	if (ret) {
2180 		err = ret;
2181 		goto fail;
2182 	}
2183 
2184 	ret = setup_bdi(fs_info, &fs_info->bdi);
2185 	if (ret) {
2186 		err = ret;
2187 		goto fail_srcu;
2188 	}
2189 
2190 	ret = percpu_counter_init(&fs_info->dirty_metadata_bytes, 0, GFP_KERNEL);
2191 	if (ret) {
2192 		err = ret;
2193 		goto fail_bdi;
2194 	}
2195 	fs_info->dirty_metadata_batch = PAGE_CACHE_SIZE *
2196 					(1 + ilog2(nr_cpu_ids));
2197 
2198 	ret = percpu_counter_init(&fs_info->delalloc_bytes, 0, GFP_KERNEL);
2199 	if (ret) {
2200 		err = ret;
2201 		goto fail_dirty_metadata_bytes;
2202 	}
2203 
2204 	ret = percpu_counter_init(&fs_info->bio_counter, 0, GFP_KERNEL);
2205 	if (ret) {
2206 		err = ret;
2207 		goto fail_delalloc_bytes;
2208 	}
2209 
2210 	fs_info->btree_inode = new_inode(sb);
2211 	if (!fs_info->btree_inode) {
2212 		err = -ENOMEM;
2213 		goto fail_bio_counter;
2214 	}
2215 
2216 	mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
2217 
2218 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
2219 	INIT_RADIX_TREE(&fs_info->buffer_radix, GFP_ATOMIC);
2220 	INIT_LIST_HEAD(&fs_info->trans_list);
2221 	INIT_LIST_HEAD(&fs_info->dead_roots);
2222 	INIT_LIST_HEAD(&fs_info->delayed_iputs);
2223 	INIT_LIST_HEAD(&fs_info->delalloc_roots);
2224 	INIT_LIST_HEAD(&fs_info->caching_block_groups);
2225 	spin_lock_init(&fs_info->delalloc_root_lock);
2226 	spin_lock_init(&fs_info->trans_lock);
2227 	spin_lock_init(&fs_info->fs_roots_radix_lock);
2228 	spin_lock_init(&fs_info->delayed_iput_lock);
2229 	spin_lock_init(&fs_info->defrag_inodes_lock);
2230 	spin_lock_init(&fs_info->free_chunk_lock);
2231 	spin_lock_init(&fs_info->tree_mod_seq_lock);
2232 	spin_lock_init(&fs_info->super_lock);
2233 	spin_lock_init(&fs_info->qgroup_op_lock);
2234 	spin_lock_init(&fs_info->buffer_lock);
2235 	spin_lock_init(&fs_info->unused_bgs_lock);
2236 	rwlock_init(&fs_info->tree_mod_log_lock);
2237 	mutex_init(&fs_info->reloc_mutex);
2238 	mutex_init(&fs_info->delalloc_root_mutex);
2239 	seqlock_init(&fs_info->profiles_lock);
2240 
2241 	init_completion(&fs_info->kobj_unregister);
2242 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
2243 	INIT_LIST_HEAD(&fs_info->space_info);
2244 	INIT_LIST_HEAD(&fs_info->tree_mod_seq_list);
2245 	INIT_LIST_HEAD(&fs_info->unused_bgs);
2246 	btrfs_mapping_init(&fs_info->mapping_tree);
2247 	btrfs_init_block_rsv(&fs_info->global_block_rsv,
2248 			     BTRFS_BLOCK_RSV_GLOBAL);
2249 	btrfs_init_block_rsv(&fs_info->delalloc_block_rsv,
2250 			     BTRFS_BLOCK_RSV_DELALLOC);
2251 	btrfs_init_block_rsv(&fs_info->trans_block_rsv, BTRFS_BLOCK_RSV_TRANS);
2252 	btrfs_init_block_rsv(&fs_info->chunk_block_rsv, BTRFS_BLOCK_RSV_CHUNK);
2253 	btrfs_init_block_rsv(&fs_info->empty_block_rsv, BTRFS_BLOCK_RSV_EMPTY);
2254 	btrfs_init_block_rsv(&fs_info->delayed_block_rsv,
2255 			     BTRFS_BLOCK_RSV_DELOPS);
2256 	atomic_set(&fs_info->nr_async_submits, 0);
2257 	atomic_set(&fs_info->async_delalloc_pages, 0);
2258 	atomic_set(&fs_info->async_submit_draining, 0);
2259 	atomic_set(&fs_info->nr_async_bios, 0);
2260 	atomic_set(&fs_info->defrag_running, 0);
2261 	atomic_set(&fs_info->qgroup_op_seq, 0);
2262 	atomic64_set(&fs_info->tree_mod_seq, 0);
2263 	fs_info->sb = sb;
2264 	fs_info->max_inline = BTRFS_DEFAULT_MAX_INLINE;
2265 	fs_info->metadata_ratio = 0;
2266 	fs_info->defrag_inodes = RB_ROOT;
2267 	fs_info->free_chunk_space = 0;
2268 	fs_info->tree_mod_log = RB_ROOT;
2269 	fs_info->commit_interval = BTRFS_DEFAULT_COMMIT_INTERVAL;
2270 	fs_info->avg_delayed_ref_runtime = div64_u64(NSEC_PER_SEC, 64);
2271 	/* readahead state */
2272 	INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
2273 	spin_lock_init(&fs_info->reada_lock);
2274 
2275 	fs_info->thread_pool_size = min_t(unsigned long,
2276 					  num_online_cpus() + 2, 8);
2277 
2278 	INIT_LIST_HEAD(&fs_info->ordered_roots);
2279 	spin_lock_init(&fs_info->ordered_root_lock);
2280 	fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
2281 					GFP_NOFS);
2282 	if (!fs_info->delayed_root) {
2283 		err = -ENOMEM;
2284 		goto fail_iput;
2285 	}
2286 	btrfs_init_delayed_root(fs_info->delayed_root);
2287 
2288 	mutex_init(&fs_info->scrub_lock);
2289 	atomic_set(&fs_info->scrubs_running, 0);
2290 	atomic_set(&fs_info->scrub_pause_req, 0);
2291 	atomic_set(&fs_info->scrubs_paused, 0);
2292 	atomic_set(&fs_info->scrub_cancel_req, 0);
2293 	init_waitqueue_head(&fs_info->replace_wait);
2294 	init_waitqueue_head(&fs_info->scrub_pause_wait);
2295 	fs_info->scrub_workers_refcnt = 0;
2296 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2297 	fs_info->check_integrity_print_mask = 0;
2298 #endif
2299 
2300 	spin_lock_init(&fs_info->balance_lock);
2301 	mutex_init(&fs_info->balance_mutex);
2302 	atomic_set(&fs_info->balance_running, 0);
2303 	atomic_set(&fs_info->balance_pause_req, 0);
2304 	atomic_set(&fs_info->balance_cancel_req, 0);
2305 	fs_info->balance_ctl = NULL;
2306 	init_waitqueue_head(&fs_info->balance_wait_q);
2307 	btrfs_init_async_reclaim_work(&fs_info->async_reclaim_work);
2308 
2309 	sb->s_blocksize = 4096;
2310 	sb->s_blocksize_bits = blksize_bits(4096);
2311 	sb->s_bdi = &fs_info->bdi;
2312 
2313 	fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2314 	set_nlink(fs_info->btree_inode, 1);
2315 	/*
2316 	 * we set the i_size on the btree inode to the max possible int.
2317 	 * the real end of the address space is determined by all of
2318 	 * the devices in the system
2319 	 */
2320 	fs_info->btree_inode->i_size = OFFSET_MAX;
2321 	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2322 	fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2323 
2324 	RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2325 	extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2326 			     fs_info->btree_inode->i_mapping);
2327 	BTRFS_I(fs_info->btree_inode)->io_tree.track_uptodate = 0;
2328 	extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2329 
2330 	BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2331 
2332 	BTRFS_I(fs_info->btree_inode)->root = tree_root;
2333 	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2334 	       sizeof(struct btrfs_key));
2335 	set_bit(BTRFS_INODE_DUMMY,
2336 		&BTRFS_I(fs_info->btree_inode)->runtime_flags);
2337 	btrfs_insert_inode_hash(fs_info->btree_inode);
2338 
2339 	spin_lock_init(&fs_info->block_group_cache_lock);
2340 	fs_info->block_group_cache_tree = RB_ROOT;
2341 	fs_info->first_logical_byte = (u64)-1;
2342 
2343 	extent_io_tree_init(&fs_info->freed_extents[0],
2344 			     fs_info->btree_inode->i_mapping);
2345 	extent_io_tree_init(&fs_info->freed_extents[1],
2346 			     fs_info->btree_inode->i_mapping);
2347 	fs_info->pinned_extents = &fs_info->freed_extents[0];
2348 	fs_info->do_barriers = 1;
2349 
2350 
2351 	mutex_init(&fs_info->ordered_operations_mutex);
2352 	mutex_init(&fs_info->ordered_extent_flush_mutex);
2353 	mutex_init(&fs_info->tree_log_mutex);
2354 	mutex_init(&fs_info->chunk_mutex);
2355 	mutex_init(&fs_info->transaction_kthread_mutex);
2356 	mutex_init(&fs_info->cleaner_mutex);
2357 	mutex_init(&fs_info->volume_mutex);
2358 	init_rwsem(&fs_info->commit_root_sem);
2359 	init_rwsem(&fs_info->cleanup_work_sem);
2360 	init_rwsem(&fs_info->subvol_sem);
2361 	sema_init(&fs_info->uuid_tree_rescan_sem, 1);
2362 	fs_info->dev_replace.lock_owner = 0;
2363 	atomic_set(&fs_info->dev_replace.nesting_level, 0);
2364 	mutex_init(&fs_info->dev_replace.lock_finishing_cancel_unmount);
2365 	mutex_init(&fs_info->dev_replace.lock_management_lock);
2366 	mutex_init(&fs_info->dev_replace.lock);
2367 
2368 	spin_lock_init(&fs_info->qgroup_lock);
2369 	mutex_init(&fs_info->qgroup_ioctl_lock);
2370 	fs_info->qgroup_tree = RB_ROOT;
2371 	fs_info->qgroup_op_tree = RB_ROOT;
2372 	INIT_LIST_HEAD(&fs_info->dirty_qgroups);
2373 	fs_info->qgroup_seq = 1;
2374 	fs_info->quota_enabled = 0;
2375 	fs_info->pending_quota_state = 0;
2376 	fs_info->qgroup_ulist = NULL;
2377 	mutex_init(&fs_info->qgroup_rescan_lock);
2378 
2379 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2380 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2381 
2382 	init_waitqueue_head(&fs_info->transaction_throttle);
2383 	init_waitqueue_head(&fs_info->transaction_wait);
2384 	init_waitqueue_head(&fs_info->transaction_blocked_wait);
2385 	init_waitqueue_head(&fs_info->async_submit_wait);
2386 
2387 	ret = btrfs_alloc_stripe_hash_table(fs_info);
2388 	if (ret) {
2389 		err = ret;
2390 		goto fail_alloc;
2391 	}
2392 
2393 	__setup_root(4096, 4096, 4096, tree_root,
2394 		     fs_info, BTRFS_ROOT_TREE_OBJECTID);
2395 
2396 	invalidate_bdev(fs_devices->latest_bdev);
2397 
2398 	/*
2399 	 * Read super block and check the signature bytes only
2400 	 */
2401 	bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2402 	if (!bh) {
2403 		err = -EINVAL;
2404 		goto fail_alloc;
2405 	}
2406 
2407 	/*
2408 	 * We want to check superblock checksum, the type is stored inside.
2409 	 * Pass the whole disk block of size BTRFS_SUPER_INFO_SIZE (4k).
2410 	 */
2411 	if (btrfs_check_super_csum(bh->b_data)) {
2412 		printk(KERN_ERR "BTRFS: superblock checksum mismatch\n");
2413 		err = -EINVAL;
2414 		goto fail_alloc;
2415 	}
2416 
2417 	/*
2418 	 * super_copy is zeroed at allocation time and we never touch the
2419 	 * following bytes up to INFO_SIZE, the checksum is calculated from
2420 	 * the whole block of INFO_SIZE
2421 	 */
2422 	memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2423 	memcpy(fs_info->super_for_commit, fs_info->super_copy,
2424 	       sizeof(*fs_info->super_for_commit));
2425 	brelse(bh);
2426 
2427 	memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2428 
2429 	ret = btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2430 	if (ret) {
2431 		printk(KERN_ERR "BTRFS: superblock contains fatal errors\n");
2432 		err = -EINVAL;
2433 		goto fail_alloc;
2434 	}
2435 
2436 	disk_super = fs_info->super_copy;
2437 	if (!btrfs_super_root(disk_super))
2438 		goto fail_alloc;
2439 
2440 	/* check FS state, whether FS is broken. */
2441 	if (btrfs_super_flags(disk_super) & BTRFS_SUPER_FLAG_ERROR)
2442 		set_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state);
2443 
2444 	/*
2445 	 * run through our array of backup supers and setup
2446 	 * our ring pointer to the oldest one
2447 	 */
2448 	generation = btrfs_super_generation(disk_super);
2449 	find_oldest_super_backup(fs_info, generation);
2450 
2451 	/*
2452 	 * In the long term, we'll store the compression type in the super
2453 	 * block, and it'll be used for per file compression control.
2454 	 */
2455 	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2456 
2457 	ret = btrfs_parse_options(tree_root, options);
2458 	if (ret) {
2459 		err = ret;
2460 		goto fail_alloc;
2461 	}
2462 
2463 	features = btrfs_super_incompat_flags(disk_super) &
2464 		~BTRFS_FEATURE_INCOMPAT_SUPP;
2465 	if (features) {
2466 		printk(KERN_ERR "BTRFS: couldn't mount because of "
2467 		       "unsupported optional features (%Lx).\n",
2468 		       features);
2469 		err = -EINVAL;
2470 		goto fail_alloc;
2471 	}
2472 
2473 	/*
2474 	 * Leafsize and nodesize were always equal, this is only a sanity check.
2475 	 */
2476 	if (le32_to_cpu(disk_super->__unused_leafsize) !=
2477 	    btrfs_super_nodesize(disk_super)) {
2478 		printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2479 		       "blocksizes don't match.  node %d leaf %d\n",
2480 		       btrfs_super_nodesize(disk_super),
2481 		       le32_to_cpu(disk_super->__unused_leafsize));
2482 		err = -EINVAL;
2483 		goto fail_alloc;
2484 	}
2485 	if (btrfs_super_nodesize(disk_super) > BTRFS_MAX_METADATA_BLOCKSIZE) {
2486 		printk(KERN_ERR "BTRFS: couldn't mount because metadata "
2487 		       "blocksize (%d) was too large\n",
2488 		       btrfs_super_nodesize(disk_super));
2489 		err = -EINVAL;
2490 		goto fail_alloc;
2491 	}
2492 
2493 	features = btrfs_super_incompat_flags(disk_super);
2494 	features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2495 	if (tree_root->fs_info->compress_type == BTRFS_COMPRESS_LZO)
2496 		features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2497 
2498 	if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
2499 		printk(KERN_ERR "BTRFS: has skinny extents\n");
2500 
2501 	/*
2502 	 * flag our filesystem as having big metadata blocks if
2503 	 * they are bigger than the page size
2504 	 */
2505 	if (btrfs_super_nodesize(disk_super) > PAGE_CACHE_SIZE) {
2506 		if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
2507 			printk(KERN_INFO "BTRFS: flagging fs with big metadata feature\n");
2508 		features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
2509 	}
2510 
2511 	nodesize = btrfs_super_nodesize(disk_super);
2512 	sectorsize = btrfs_super_sectorsize(disk_super);
2513 	stripesize = btrfs_super_stripesize(disk_super);
2514 	fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
2515 	fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
2516 
2517 	/*
2518 	 * mixed block groups end up with duplicate but slightly offset
2519 	 * extent buffers for the same range.  It leads to corruptions
2520 	 */
2521 	if ((features & BTRFS_FEATURE_INCOMPAT_MIXED_GROUPS) &&
2522 	    (sectorsize != nodesize)) {
2523 		printk(KERN_WARNING "BTRFS: unequal leaf/node/sector sizes "
2524 				"are not allowed for mixed block groups on %s\n",
2525 				sb->s_id);
2526 		goto fail_alloc;
2527 	}
2528 
2529 	/*
2530 	 * Needn't use the lock because there is no other task which will
2531 	 * update the flag.
2532 	 */
2533 	btrfs_set_super_incompat_flags(disk_super, features);
2534 
2535 	features = btrfs_super_compat_ro_flags(disk_super) &
2536 		~BTRFS_FEATURE_COMPAT_RO_SUPP;
2537 	if (!(sb->s_flags & MS_RDONLY) && features) {
2538 		printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2539 		       "unsupported option features (%Lx).\n",
2540 		       features);
2541 		err = -EINVAL;
2542 		goto fail_alloc;
2543 	}
2544 
2545 	max_active = fs_info->thread_pool_size;
2546 
2547 	fs_info->workers =
2548 		btrfs_alloc_workqueue("worker", flags | WQ_HIGHPRI,
2549 				      max_active, 16);
2550 
2551 	fs_info->delalloc_workers =
2552 		btrfs_alloc_workqueue("delalloc", flags, max_active, 2);
2553 
2554 	fs_info->flush_workers =
2555 		btrfs_alloc_workqueue("flush_delalloc", flags, max_active, 0);
2556 
2557 	fs_info->caching_workers =
2558 		btrfs_alloc_workqueue("cache", flags, max_active, 0);
2559 
2560 	/*
2561 	 * a higher idle thresh on the submit workers makes it much more
2562 	 * likely that bios will be send down in a sane order to the
2563 	 * devices
2564 	 */
2565 	fs_info->submit_workers =
2566 		btrfs_alloc_workqueue("submit", flags,
2567 				      min_t(u64, fs_devices->num_devices,
2568 					    max_active), 64);
2569 
2570 	fs_info->fixup_workers =
2571 		btrfs_alloc_workqueue("fixup", flags, 1, 0);
2572 
2573 	/*
2574 	 * endios are largely parallel and should have a very
2575 	 * low idle thresh
2576 	 */
2577 	fs_info->endio_workers =
2578 		btrfs_alloc_workqueue("endio", flags, max_active, 4);
2579 	fs_info->endio_meta_workers =
2580 		btrfs_alloc_workqueue("endio-meta", flags, max_active, 4);
2581 	fs_info->endio_meta_write_workers =
2582 		btrfs_alloc_workqueue("endio-meta-write", flags, max_active, 2);
2583 	fs_info->endio_raid56_workers =
2584 		btrfs_alloc_workqueue("endio-raid56", flags, max_active, 4);
2585 	fs_info->endio_repair_workers =
2586 		btrfs_alloc_workqueue("endio-repair", flags, 1, 0);
2587 	fs_info->rmw_workers =
2588 		btrfs_alloc_workqueue("rmw", flags, max_active, 2);
2589 	fs_info->endio_write_workers =
2590 		btrfs_alloc_workqueue("endio-write", flags, max_active, 2);
2591 	fs_info->endio_freespace_worker =
2592 		btrfs_alloc_workqueue("freespace-write", flags, max_active, 0);
2593 	fs_info->delayed_workers =
2594 		btrfs_alloc_workqueue("delayed-meta", flags, max_active, 0);
2595 	fs_info->readahead_workers =
2596 		btrfs_alloc_workqueue("readahead", flags, max_active, 2);
2597 	fs_info->qgroup_rescan_workers =
2598 		btrfs_alloc_workqueue("qgroup-rescan", flags, 1, 0);
2599 	fs_info->extent_workers =
2600 		btrfs_alloc_workqueue("extent-refs", flags,
2601 				      min_t(u64, fs_devices->num_devices,
2602 					    max_active), 8);
2603 
2604 	if (!(fs_info->workers && fs_info->delalloc_workers &&
2605 	      fs_info->submit_workers && fs_info->flush_workers &&
2606 	      fs_info->endio_workers && fs_info->endio_meta_workers &&
2607 	      fs_info->endio_meta_write_workers &&
2608 	      fs_info->endio_repair_workers &&
2609 	      fs_info->endio_write_workers && fs_info->endio_raid56_workers &&
2610 	      fs_info->endio_freespace_worker && fs_info->rmw_workers &&
2611 	      fs_info->caching_workers && fs_info->readahead_workers &&
2612 	      fs_info->fixup_workers && fs_info->delayed_workers &&
2613 	      fs_info->extent_workers &&
2614 	      fs_info->qgroup_rescan_workers)) {
2615 		err = -ENOMEM;
2616 		goto fail_sb_buffer;
2617 	}
2618 
2619 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2620 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2621 				    4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2622 
2623 	tree_root->nodesize = nodesize;
2624 	tree_root->sectorsize = sectorsize;
2625 	tree_root->stripesize = stripesize;
2626 
2627 	sb->s_blocksize = sectorsize;
2628 	sb->s_blocksize_bits = blksize_bits(sectorsize);
2629 
2630 	if (btrfs_super_magic(disk_super) != BTRFS_MAGIC) {
2631 		printk(KERN_INFO "BTRFS: valid FS not found on %s\n", sb->s_id);
2632 		goto fail_sb_buffer;
2633 	}
2634 
2635 	if (sectorsize != PAGE_SIZE) {
2636 		printk(KERN_WARNING "BTRFS: Incompatible sector size(%lu) "
2637 		       "found on %s\n", (unsigned long)sectorsize, sb->s_id);
2638 		goto fail_sb_buffer;
2639 	}
2640 
2641 	mutex_lock(&fs_info->chunk_mutex);
2642 	ret = btrfs_read_sys_array(tree_root);
2643 	mutex_unlock(&fs_info->chunk_mutex);
2644 	if (ret) {
2645 		printk(KERN_WARNING "BTRFS: failed to read the system "
2646 		       "array on %s\n", sb->s_id);
2647 		goto fail_sb_buffer;
2648 	}
2649 
2650 	generation = btrfs_super_chunk_root_generation(disk_super);
2651 
2652 	__setup_root(nodesize, sectorsize, stripesize, chunk_root,
2653 		     fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2654 
2655 	chunk_root->node = read_tree_block(chunk_root,
2656 					   btrfs_super_chunk_root(disk_super),
2657 					   generation);
2658 	if (!chunk_root->node ||
2659 	    !test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2660 		printk(KERN_WARNING "BTRFS: failed to read chunk root on %s\n",
2661 		       sb->s_id);
2662 		goto fail_tree_roots;
2663 	}
2664 	btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2665 	chunk_root->commit_root = btrfs_root_node(chunk_root);
2666 
2667 	read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2668 	   btrfs_header_chunk_tree_uuid(chunk_root->node), BTRFS_UUID_SIZE);
2669 
2670 	ret = btrfs_read_chunk_tree(chunk_root);
2671 	if (ret) {
2672 		printk(KERN_WARNING "BTRFS: failed to read chunk tree on %s\n",
2673 		       sb->s_id);
2674 		goto fail_tree_roots;
2675 	}
2676 
2677 	/*
2678 	 * keep the device that is marked to be the target device for the
2679 	 * dev_replace procedure
2680 	 */
2681 	btrfs_close_extra_devices(fs_info, fs_devices, 0);
2682 
2683 	if (!fs_devices->latest_bdev) {
2684 		printk(KERN_CRIT "BTRFS: failed to read devices on %s\n",
2685 		       sb->s_id);
2686 		goto fail_tree_roots;
2687 	}
2688 
2689 retry_root_backup:
2690 	generation = btrfs_super_generation(disk_super);
2691 
2692 	tree_root->node = read_tree_block(tree_root,
2693 					  btrfs_super_root(disk_super),
2694 					  generation);
2695 	if (!tree_root->node ||
2696 	    !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2697 		printk(KERN_WARNING "BTRFS: failed to read tree root on %s\n",
2698 		       sb->s_id);
2699 
2700 		goto recovery_tree_root;
2701 	}
2702 
2703 	btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2704 	tree_root->commit_root = btrfs_root_node(tree_root);
2705 	btrfs_set_root_refs(&tree_root->root_item, 1);
2706 
2707 	location.objectid = BTRFS_EXTENT_TREE_OBJECTID;
2708 	location.type = BTRFS_ROOT_ITEM_KEY;
2709 	location.offset = 0;
2710 
2711 	extent_root = btrfs_read_tree_root(tree_root, &location);
2712 	if (IS_ERR(extent_root)) {
2713 		ret = PTR_ERR(extent_root);
2714 		goto recovery_tree_root;
2715 	}
2716 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &extent_root->state);
2717 	fs_info->extent_root = extent_root;
2718 
2719 	location.objectid = BTRFS_DEV_TREE_OBJECTID;
2720 	dev_root = btrfs_read_tree_root(tree_root, &location);
2721 	if (IS_ERR(dev_root)) {
2722 		ret = PTR_ERR(dev_root);
2723 		goto recovery_tree_root;
2724 	}
2725 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &dev_root->state);
2726 	fs_info->dev_root = dev_root;
2727 	btrfs_init_devices_late(fs_info);
2728 
2729 	location.objectid = BTRFS_CSUM_TREE_OBJECTID;
2730 	csum_root = btrfs_read_tree_root(tree_root, &location);
2731 	if (IS_ERR(csum_root)) {
2732 		ret = PTR_ERR(csum_root);
2733 		goto recovery_tree_root;
2734 	}
2735 	set_bit(BTRFS_ROOT_TRACK_DIRTY, &csum_root->state);
2736 	fs_info->csum_root = csum_root;
2737 
2738 	location.objectid = BTRFS_QUOTA_TREE_OBJECTID;
2739 	quota_root = btrfs_read_tree_root(tree_root, &location);
2740 	if (!IS_ERR(quota_root)) {
2741 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &quota_root->state);
2742 		fs_info->quota_enabled = 1;
2743 		fs_info->pending_quota_state = 1;
2744 		fs_info->quota_root = quota_root;
2745 	}
2746 
2747 	location.objectid = BTRFS_UUID_TREE_OBJECTID;
2748 	uuid_root = btrfs_read_tree_root(tree_root, &location);
2749 	if (IS_ERR(uuid_root)) {
2750 		ret = PTR_ERR(uuid_root);
2751 		if (ret != -ENOENT)
2752 			goto recovery_tree_root;
2753 		create_uuid_tree = true;
2754 		check_uuid_tree = false;
2755 	} else {
2756 		set_bit(BTRFS_ROOT_TRACK_DIRTY, &uuid_root->state);
2757 		fs_info->uuid_root = uuid_root;
2758 		create_uuid_tree = false;
2759 		check_uuid_tree =
2760 		    generation != btrfs_super_uuid_tree_generation(disk_super);
2761 	}
2762 
2763 	fs_info->generation = generation;
2764 	fs_info->last_trans_committed = generation;
2765 
2766 	ret = btrfs_recover_balance(fs_info);
2767 	if (ret) {
2768 		printk(KERN_WARNING "BTRFS: failed to recover balance\n");
2769 		goto fail_block_groups;
2770 	}
2771 
2772 	ret = btrfs_init_dev_stats(fs_info);
2773 	if (ret) {
2774 		printk(KERN_ERR "BTRFS: failed to init dev_stats: %d\n",
2775 		       ret);
2776 		goto fail_block_groups;
2777 	}
2778 
2779 	ret = btrfs_init_dev_replace(fs_info);
2780 	if (ret) {
2781 		pr_err("BTRFS: failed to init dev_replace: %d\n", ret);
2782 		goto fail_block_groups;
2783 	}
2784 
2785 	btrfs_close_extra_devices(fs_info, fs_devices, 1);
2786 
2787 	ret = btrfs_sysfs_add_one(fs_info);
2788 	if (ret) {
2789 		pr_err("BTRFS: failed to init sysfs interface: %d\n", ret);
2790 		goto fail_block_groups;
2791 	}
2792 
2793 	ret = btrfs_init_space_info(fs_info);
2794 	if (ret) {
2795 		printk(KERN_ERR "BTRFS: Failed to initial space info: %d\n", ret);
2796 		goto fail_sysfs;
2797 	}
2798 
2799 	ret = btrfs_read_block_groups(extent_root);
2800 	if (ret) {
2801 		printk(KERN_ERR "BTRFS: Failed to read block groups: %d\n", ret);
2802 		goto fail_sysfs;
2803 	}
2804 	fs_info->num_tolerated_disk_barrier_failures =
2805 		btrfs_calc_num_tolerated_disk_barrier_failures(fs_info);
2806 	if (fs_info->fs_devices->missing_devices >
2807 	     fs_info->num_tolerated_disk_barrier_failures &&
2808 	    !(sb->s_flags & MS_RDONLY)) {
2809 		printk(KERN_WARNING "BTRFS: "
2810 			"too many missing devices, writeable mount is not allowed\n");
2811 		goto fail_sysfs;
2812 	}
2813 
2814 	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2815 					       "btrfs-cleaner");
2816 	if (IS_ERR(fs_info->cleaner_kthread))
2817 		goto fail_sysfs;
2818 
2819 	fs_info->transaction_kthread = kthread_run(transaction_kthread,
2820 						   tree_root,
2821 						   "btrfs-transaction");
2822 	if (IS_ERR(fs_info->transaction_kthread))
2823 		goto fail_cleaner;
2824 
2825 	if (!btrfs_test_opt(tree_root, SSD) &&
2826 	    !btrfs_test_opt(tree_root, NOSSD) &&
2827 	    !fs_info->fs_devices->rotating) {
2828 		printk(KERN_INFO "BTRFS: detected SSD devices, enabling SSD "
2829 		       "mode\n");
2830 		btrfs_set_opt(fs_info->mount_opt, SSD);
2831 	}
2832 
2833 	/* Set the real inode map cache flag */
2834 	if (btrfs_test_opt(tree_root, CHANGE_INODE_CACHE))
2835 		btrfs_set_opt(tree_root->fs_info->mount_opt, INODE_MAP_CACHE);
2836 
2837 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
2838 	if (btrfs_test_opt(tree_root, CHECK_INTEGRITY)) {
2839 		ret = btrfsic_mount(tree_root, fs_devices,
2840 				    btrfs_test_opt(tree_root,
2841 					CHECK_INTEGRITY_INCLUDING_EXTENT_DATA) ?
2842 				    1 : 0,
2843 				    fs_info->check_integrity_print_mask);
2844 		if (ret)
2845 			printk(KERN_WARNING "BTRFS: failed to initialize"
2846 			       " integrity check module %s\n", sb->s_id);
2847 	}
2848 #endif
2849 	ret = btrfs_read_qgroup_config(fs_info);
2850 	if (ret)
2851 		goto fail_trans_kthread;
2852 
2853 	/* do not make disk changes in broken FS */
2854 	if (btrfs_super_log_root(disk_super) != 0) {
2855 		u64 bytenr = btrfs_super_log_root(disk_super);
2856 
2857 		if (fs_devices->rw_devices == 0) {
2858 			printk(KERN_WARNING "BTRFS: log replay required "
2859 			       "on RO media\n");
2860 			err = -EIO;
2861 			goto fail_qgroup;
2862 		}
2863 
2864 		log_tree_root = btrfs_alloc_root(fs_info);
2865 		if (!log_tree_root) {
2866 			err = -ENOMEM;
2867 			goto fail_qgroup;
2868 		}
2869 
2870 		__setup_root(nodesize, sectorsize, stripesize,
2871 			     log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2872 
2873 		log_tree_root->node = read_tree_block(tree_root, bytenr,
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 	fs_info->open = 1;
2981 
2982 	return 0;
2983 
2984 fail_qgroup:
2985 	btrfs_free_qgroup_config(fs_info);
2986 fail_trans_kthread:
2987 	kthread_stop(fs_info->transaction_kthread);
2988 	btrfs_cleanup_transaction(fs_info->tree_root);
2989 	btrfs_free_fs_roots(fs_info);
2990 fail_cleaner:
2991 	kthread_stop(fs_info->cleaner_kthread);
2992 
2993 	/*
2994 	 * make sure we're done with the btree inode before we stop our
2995 	 * kthreads
2996 	 */
2997 	filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2998 
2999 fail_sysfs:
3000 	btrfs_sysfs_remove_one(fs_info);
3001 
3002 fail_block_groups:
3003 	btrfs_put_block_group_cache(fs_info);
3004 	btrfs_free_block_groups(fs_info);
3005 
3006 fail_tree_roots:
3007 	free_root_pointers(fs_info, 1);
3008 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3009 
3010 fail_sb_buffer:
3011 	btrfs_stop_all_workers(fs_info);
3012 fail_alloc:
3013 fail_iput:
3014 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
3015 
3016 	iput(fs_info->btree_inode);
3017 fail_bio_counter:
3018 	percpu_counter_destroy(&fs_info->bio_counter);
3019 fail_delalloc_bytes:
3020 	percpu_counter_destroy(&fs_info->delalloc_bytes);
3021 fail_dirty_metadata_bytes:
3022 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3023 fail_bdi:
3024 	bdi_destroy(&fs_info->bdi);
3025 fail_srcu:
3026 	cleanup_srcu_struct(&fs_info->subvol_srcu);
3027 fail:
3028 	btrfs_free_stripe_hash_table(fs_info);
3029 	btrfs_close_devices(fs_info->fs_devices);
3030 	return err;
3031 
3032 recovery_tree_root:
3033 	if (!btrfs_test_opt(tree_root, RECOVERY))
3034 		goto fail_tree_roots;
3035 
3036 	free_root_pointers(fs_info, 0);
3037 
3038 	/* don't use the log in recovery mode, it won't be valid */
3039 	btrfs_set_super_log_root(disk_super, 0);
3040 
3041 	/* we can't trust the free space cache either */
3042 	btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
3043 
3044 	ret = next_root_backup(fs_info, fs_info->super_copy,
3045 			       &num_backups_tried, &backup_index);
3046 	if (ret == -1)
3047 		goto fail_block_groups;
3048 	goto retry_root_backup;
3049 }
3050 
3051 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
3052 {
3053 	if (uptodate) {
3054 		set_buffer_uptodate(bh);
3055 	} else {
3056 		struct btrfs_device *device = (struct btrfs_device *)
3057 			bh->b_private;
3058 
3059 		printk_ratelimited_in_rcu(KERN_WARNING "BTRFS: lost page write due to "
3060 					  "I/O error on %s\n",
3061 					  rcu_str_deref(device->name));
3062 		/* note, we dont' set_buffer_write_io_error because we have
3063 		 * our own ways of dealing with the IO errors
3064 		 */
3065 		clear_buffer_uptodate(bh);
3066 		btrfs_dev_stat_inc_and_print(device, BTRFS_DEV_STAT_WRITE_ERRS);
3067 	}
3068 	unlock_buffer(bh);
3069 	put_bh(bh);
3070 }
3071 
3072 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
3073 {
3074 	struct buffer_head *bh;
3075 	struct buffer_head *latest = NULL;
3076 	struct btrfs_super_block *super;
3077 	int i;
3078 	u64 transid = 0;
3079 	u64 bytenr;
3080 
3081 	/* we would like to check all the supers, but that would make
3082 	 * a btrfs mount succeed after a mkfs from a different FS.
3083 	 * So, we need to add a special mount option to scan for
3084 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
3085 	 */
3086 	for (i = 0; i < 1; i++) {
3087 		bytenr = btrfs_sb_offset(i);
3088 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3089 					i_size_read(bdev->bd_inode))
3090 			break;
3091 		bh = __bread(bdev, bytenr / 4096,
3092 					BTRFS_SUPER_INFO_SIZE);
3093 		if (!bh)
3094 			continue;
3095 
3096 		super = (struct btrfs_super_block *)bh->b_data;
3097 		if (btrfs_super_bytenr(super) != bytenr ||
3098 		    btrfs_super_magic(super) != BTRFS_MAGIC) {
3099 			brelse(bh);
3100 			continue;
3101 		}
3102 
3103 		if (!latest || btrfs_super_generation(super) > transid) {
3104 			brelse(latest);
3105 			latest = bh;
3106 			transid = btrfs_super_generation(super);
3107 		} else {
3108 			brelse(bh);
3109 		}
3110 	}
3111 	return latest;
3112 }
3113 
3114 /*
3115  * this should be called twice, once with wait == 0 and
3116  * once with wait == 1.  When wait == 0 is done, all the buffer heads
3117  * we write are pinned.
3118  *
3119  * They are released when wait == 1 is done.
3120  * max_mirrors must be the same for both runs, and it indicates how
3121  * many supers on this one device should be written.
3122  *
3123  * max_mirrors == 0 means to write them all.
3124  */
3125 static int write_dev_supers(struct btrfs_device *device,
3126 			    struct btrfs_super_block *sb,
3127 			    int do_barriers, int wait, int max_mirrors)
3128 {
3129 	struct buffer_head *bh;
3130 	int i;
3131 	int ret;
3132 	int errors = 0;
3133 	u32 crc;
3134 	u64 bytenr;
3135 
3136 	if (max_mirrors == 0)
3137 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
3138 
3139 	for (i = 0; i < max_mirrors; i++) {
3140 		bytenr = btrfs_sb_offset(i);
3141 		if (bytenr + BTRFS_SUPER_INFO_SIZE >=
3142 		    device->commit_total_bytes)
3143 			break;
3144 
3145 		if (wait) {
3146 			bh = __find_get_block(device->bdev, bytenr / 4096,
3147 					      BTRFS_SUPER_INFO_SIZE);
3148 			if (!bh) {
3149 				errors++;
3150 				continue;
3151 			}
3152 			wait_on_buffer(bh);
3153 			if (!buffer_uptodate(bh))
3154 				errors++;
3155 
3156 			/* drop our reference */
3157 			brelse(bh);
3158 
3159 			/* drop the reference from the wait == 0 run */
3160 			brelse(bh);
3161 			continue;
3162 		} else {
3163 			btrfs_set_super_bytenr(sb, bytenr);
3164 
3165 			crc = ~(u32)0;
3166 			crc = btrfs_csum_data((char *)sb +
3167 					      BTRFS_CSUM_SIZE, crc,
3168 					      BTRFS_SUPER_INFO_SIZE -
3169 					      BTRFS_CSUM_SIZE);
3170 			btrfs_csum_final(crc, sb->csum);
3171 
3172 			/*
3173 			 * one reference for us, and we leave it for the
3174 			 * caller
3175 			 */
3176 			bh = __getblk(device->bdev, bytenr / 4096,
3177 				      BTRFS_SUPER_INFO_SIZE);
3178 			if (!bh) {
3179 				printk(KERN_ERR "BTRFS: couldn't get super "
3180 				       "buffer head for bytenr %Lu\n", bytenr);
3181 				errors++;
3182 				continue;
3183 			}
3184 
3185 			memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
3186 
3187 			/* one reference for submit_bh */
3188 			get_bh(bh);
3189 
3190 			set_buffer_uptodate(bh);
3191 			lock_buffer(bh);
3192 			bh->b_end_io = btrfs_end_buffer_write_sync;
3193 			bh->b_private = device;
3194 		}
3195 
3196 		/*
3197 		 * we fua the first super.  The others we allow
3198 		 * to go down lazy.
3199 		 */
3200 		if (i == 0)
3201 			ret = btrfsic_submit_bh(WRITE_FUA, bh);
3202 		else
3203 			ret = btrfsic_submit_bh(WRITE_SYNC, bh);
3204 		if (ret)
3205 			errors++;
3206 	}
3207 	return errors < i ? 0 : -1;
3208 }
3209 
3210 /*
3211  * endio for the write_dev_flush, this will wake anyone waiting
3212  * for the barrier when it is done
3213  */
3214 static void btrfs_end_empty_barrier(struct bio *bio, int err)
3215 {
3216 	if (err) {
3217 		if (err == -EOPNOTSUPP)
3218 			set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
3219 		clear_bit(BIO_UPTODATE, &bio->bi_flags);
3220 	}
3221 	if (bio->bi_private)
3222 		complete(bio->bi_private);
3223 	bio_put(bio);
3224 }
3225 
3226 /*
3227  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
3228  * sent down.  With wait == 1, it waits for the previous flush.
3229  *
3230  * any device where the flush fails with eopnotsupp are flagged as not-barrier
3231  * capable
3232  */
3233 static int write_dev_flush(struct btrfs_device *device, int wait)
3234 {
3235 	struct bio *bio;
3236 	int ret = 0;
3237 
3238 	if (device->nobarriers)
3239 		return 0;
3240 
3241 	if (wait) {
3242 		bio = device->flush_bio;
3243 		if (!bio)
3244 			return 0;
3245 
3246 		wait_for_completion(&device->flush_wait);
3247 
3248 		if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
3249 			printk_in_rcu("BTRFS: disabling barriers on dev %s\n",
3250 				      rcu_str_deref(device->name));
3251 			device->nobarriers = 1;
3252 		} else if (!bio_flagged(bio, BIO_UPTODATE)) {
3253 			ret = -EIO;
3254 			btrfs_dev_stat_inc_and_print(device,
3255 				BTRFS_DEV_STAT_FLUSH_ERRS);
3256 		}
3257 
3258 		/* drop the reference from the wait == 0 run */
3259 		bio_put(bio);
3260 		device->flush_bio = NULL;
3261 
3262 		return ret;
3263 	}
3264 
3265 	/*
3266 	 * one reference for us, and we leave it for the
3267 	 * caller
3268 	 */
3269 	device->flush_bio = NULL;
3270 	bio = btrfs_io_bio_alloc(GFP_NOFS, 0);
3271 	if (!bio)
3272 		return -ENOMEM;
3273 
3274 	bio->bi_end_io = btrfs_end_empty_barrier;
3275 	bio->bi_bdev = device->bdev;
3276 	init_completion(&device->flush_wait);
3277 	bio->bi_private = &device->flush_wait;
3278 	device->flush_bio = bio;
3279 
3280 	bio_get(bio);
3281 	btrfsic_submit_bio(WRITE_FLUSH, bio);
3282 
3283 	return 0;
3284 }
3285 
3286 /*
3287  * send an empty flush down to each device in parallel,
3288  * then wait for them
3289  */
3290 static int barrier_all_devices(struct btrfs_fs_info *info)
3291 {
3292 	struct list_head *head;
3293 	struct btrfs_device *dev;
3294 	int errors_send = 0;
3295 	int errors_wait = 0;
3296 	int ret;
3297 
3298 	/* send down all the barriers */
3299 	head = &info->fs_devices->devices;
3300 	list_for_each_entry_rcu(dev, head, dev_list) {
3301 		if (dev->missing)
3302 			continue;
3303 		if (!dev->bdev) {
3304 			errors_send++;
3305 			continue;
3306 		}
3307 		if (!dev->in_fs_metadata || !dev->writeable)
3308 			continue;
3309 
3310 		ret = write_dev_flush(dev, 0);
3311 		if (ret)
3312 			errors_send++;
3313 	}
3314 
3315 	/* wait for all the barriers */
3316 	list_for_each_entry_rcu(dev, head, dev_list) {
3317 		if (dev->missing)
3318 			continue;
3319 		if (!dev->bdev) {
3320 			errors_wait++;
3321 			continue;
3322 		}
3323 		if (!dev->in_fs_metadata || !dev->writeable)
3324 			continue;
3325 
3326 		ret = write_dev_flush(dev, 1);
3327 		if (ret)
3328 			errors_wait++;
3329 	}
3330 	if (errors_send > info->num_tolerated_disk_barrier_failures ||
3331 	    errors_wait > info->num_tolerated_disk_barrier_failures)
3332 		return -EIO;
3333 	return 0;
3334 }
3335 
3336 int btrfs_calc_num_tolerated_disk_barrier_failures(
3337 	struct btrfs_fs_info *fs_info)
3338 {
3339 	struct btrfs_ioctl_space_info space;
3340 	struct btrfs_space_info *sinfo;
3341 	u64 types[] = {BTRFS_BLOCK_GROUP_DATA,
3342 		       BTRFS_BLOCK_GROUP_SYSTEM,
3343 		       BTRFS_BLOCK_GROUP_METADATA,
3344 		       BTRFS_BLOCK_GROUP_DATA | BTRFS_BLOCK_GROUP_METADATA};
3345 	int num_types = 4;
3346 	int i;
3347 	int c;
3348 	int num_tolerated_disk_barrier_failures =
3349 		(int)fs_info->fs_devices->num_devices;
3350 
3351 	for (i = 0; i < num_types; i++) {
3352 		struct btrfs_space_info *tmp;
3353 
3354 		sinfo = NULL;
3355 		rcu_read_lock();
3356 		list_for_each_entry_rcu(tmp, &fs_info->space_info, list) {
3357 			if (tmp->flags == types[i]) {
3358 				sinfo = tmp;
3359 				break;
3360 			}
3361 		}
3362 		rcu_read_unlock();
3363 
3364 		if (!sinfo)
3365 			continue;
3366 
3367 		down_read(&sinfo->groups_sem);
3368 		for (c = 0; c < BTRFS_NR_RAID_TYPES; c++) {
3369 			if (!list_empty(&sinfo->block_groups[c])) {
3370 				u64 flags;
3371 
3372 				btrfs_get_block_group_info(
3373 					&sinfo->block_groups[c], &space);
3374 				if (space.total_bytes == 0 ||
3375 				    space.used_bytes == 0)
3376 					continue;
3377 				flags = space.flags;
3378 				/*
3379 				 * return
3380 				 * 0: if dup, single or RAID0 is configured for
3381 				 *    any of metadata, system or data, else
3382 				 * 1: if RAID5 is configured, or if RAID1 or
3383 				 *    RAID10 is configured and only two mirrors
3384 				 *    are used, else
3385 				 * 2: if RAID6 is configured, else
3386 				 * num_mirrors - 1: if RAID1 or RAID10 is
3387 				 *                  configured and more than
3388 				 *                  2 mirrors are used.
3389 				 */
3390 				if (num_tolerated_disk_barrier_failures > 0 &&
3391 				    ((flags & (BTRFS_BLOCK_GROUP_DUP |
3392 					       BTRFS_BLOCK_GROUP_RAID0)) ||
3393 				     ((flags & BTRFS_BLOCK_GROUP_PROFILE_MASK)
3394 				      == 0)))
3395 					num_tolerated_disk_barrier_failures = 0;
3396 				else if (num_tolerated_disk_barrier_failures > 1) {
3397 					if (flags & (BTRFS_BLOCK_GROUP_RAID1 |
3398 					    BTRFS_BLOCK_GROUP_RAID5 |
3399 					    BTRFS_BLOCK_GROUP_RAID10)) {
3400 						num_tolerated_disk_barrier_failures = 1;
3401 					} else if (flags &
3402 						   BTRFS_BLOCK_GROUP_RAID6) {
3403 						num_tolerated_disk_barrier_failures = 2;
3404 					}
3405 				}
3406 			}
3407 		}
3408 		up_read(&sinfo->groups_sem);
3409 	}
3410 
3411 	return num_tolerated_disk_barrier_failures;
3412 }
3413 
3414 static int write_all_supers(struct btrfs_root *root, int max_mirrors)
3415 {
3416 	struct list_head *head;
3417 	struct btrfs_device *dev;
3418 	struct btrfs_super_block *sb;
3419 	struct btrfs_dev_item *dev_item;
3420 	int ret;
3421 	int do_barriers;
3422 	int max_errors;
3423 	int total_errors = 0;
3424 	u64 flags;
3425 
3426 	do_barriers = !btrfs_test_opt(root, NOBARRIER);
3427 	backup_super_roots(root->fs_info);
3428 
3429 	sb = root->fs_info->super_for_commit;
3430 	dev_item = &sb->dev_item;
3431 
3432 	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
3433 	head = &root->fs_info->fs_devices->devices;
3434 	max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
3435 
3436 	if (do_barriers) {
3437 		ret = barrier_all_devices(root->fs_info);
3438 		if (ret) {
3439 			mutex_unlock(
3440 				&root->fs_info->fs_devices->device_list_mutex);
3441 			btrfs_error(root->fs_info, ret,
3442 				    "errors while submitting device barriers.");
3443 			return ret;
3444 		}
3445 	}
3446 
3447 	list_for_each_entry_rcu(dev, head, dev_list) {
3448 		if (!dev->bdev) {
3449 			total_errors++;
3450 			continue;
3451 		}
3452 		if (!dev->in_fs_metadata || !dev->writeable)
3453 			continue;
3454 
3455 		btrfs_set_stack_device_generation(dev_item, 0);
3456 		btrfs_set_stack_device_type(dev_item, dev->type);
3457 		btrfs_set_stack_device_id(dev_item, dev->devid);
3458 		btrfs_set_stack_device_total_bytes(dev_item,
3459 						   dev->commit_total_bytes);
3460 		btrfs_set_stack_device_bytes_used(dev_item,
3461 						  dev->commit_bytes_used);
3462 		btrfs_set_stack_device_io_align(dev_item, dev->io_align);
3463 		btrfs_set_stack_device_io_width(dev_item, dev->io_width);
3464 		btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
3465 		memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
3466 		memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
3467 
3468 		flags = btrfs_super_flags(sb);
3469 		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
3470 
3471 		ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
3472 		if (ret)
3473 			total_errors++;
3474 	}
3475 	if (total_errors > max_errors) {
3476 		btrfs_err(root->fs_info, "%d errors while writing supers",
3477 		       total_errors);
3478 		mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3479 
3480 		/* FUA is masked off if unsupported and can't be the reason */
3481 		btrfs_error(root->fs_info, -EIO,
3482 			    "%d errors while writing supers", total_errors);
3483 		return -EIO;
3484 	}
3485 
3486 	total_errors = 0;
3487 	list_for_each_entry_rcu(dev, head, dev_list) {
3488 		if (!dev->bdev)
3489 			continue;
3490 		if (!dev->in_fs_metadata || !dev->writeable)
3491 			continue;
3492 
3493 		ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
3494 		if (ret)
3495 			total_errors++;
3496 	}
3497 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
3498 	if (total_errors > max_errors) {
3499 		btrfs_error(root->fs_info, -EIO,
3500 			    "%d errors while writing supers", total_errors);
3501 		return -EIO;
3502 	}
3503 	return 0;
3504 }
3505 
3506 int write_ctree_super(struct btrfs_trans_handle *trans,
3507 		      struct btrfs_root *root, int max_mirrors)
3508 {
3509 	return write_all_supers(root, max_mirrors);
3510 }
3511 
3512 /* Drop a fs root from the radix tree and free it. */
3513 void btrfs_drop_and_free_fs_root(struct btrfs_fs_info *fs_info,
3514 				  struct btrfs_root *root)
3515 {
3516 	spin_lock(&fs_info->fs_roots_radix_lock);
3517 	radix_tree_delete(&fs_info->fs_roots_radix,
3518 			  (unsigned long)root->root_key.objectid);
3519 	spin_unlock(&fs_info->fs_roots_radix_lock);
3520 
3521 	if (btrfs_root_refs(&root->root_item) == 0)
3522 		synchronize_srcu(&fs_info->subvol_srcu);
3523 
3524 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3525 		btrfs_free_log(NULL, root);
3526 
3527 	if (root->free_ino_pinned)
3528 		__btrfs_remove_free_space_cache(root->free_ino_pinned);
3529 	if (root->free_ino_ctl)
3530 		__btrfs_remove_free_space_cache(root->free_ino_ctl);
3531 	free_fs_root(root);
3532 }
3533 
3534 static void free_fs_root(struct btrfs_root *root)
3535 {
3536 	iput(root->ino_cache_inode);
3537 	WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
3538 	btrfs_free_block_rsv(root, root->orphan_block_rsv);
3539 	root->orphan_block_rsv = NULL;
3540 	if (root->anon_dev)
3541 		free_anon_bdev(root->anon_dev);
3542 	if (root->subv_writers)
3543 		btrfs_free_subvolume_writers(root->subv_writers);
3544 	free_extent_buffer(root->node);
3545 	free_extent_buffer(root->commit_root);
3546 	kfree(root->free_ino_ctl);
3547 	kfree(root->free_ino_pinned);
3548 	kfree(root->name);
3549 	btrfs_put_fs_root(root);
3550 }
3551 
3552 void btrfs_free_fs_root(struct btrfs_root *root)
3553 {
3554 	free_fs_root(root);
3555 }
3556 
3557 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
3558 {
3559 	u64 root_objectid = 0;
3560 	struct btrfs_root *gang[8];
3561 	int i = 0;
3562 	int err = 0;
3563 	unsigned int ret = 0;
3564 	int index;
3565 
3566 	while (1) {
3567 		index = srcu_read_lock(&fs_info->subvol_srcu);
3568 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
3569 					     (void **)gang, root_objectid,
3570 					     ARRAY_SIZE(gang));
3571 		if (!ret) {
3572 			srcu_read_unlock(&fs_info->subvol_srcu, index);
3573 			break;
3574 		}
3575 		root_objectid = gang[ret - 1]->root_key.objectid + 1;
3576 
3577 		for (i = 0; i < ret; i++) {
3578 			/* Avoid to grab roots in dead_roots */
3579 			if (btrfs_root_refs(&gang[i]->root_item) == 0) {
3580 				gang[i] = NULL;
3581 				continue;
3582 			}
3583 			/* grab all the search result for later use */
3584 			gang[i] = btrfs_grab_fs_root(gang[i]);
3585 		}
3586 		srcu_read_unlock(&fs_info->subvol_srcu, index);
3587 
3588 		for (i = 0; i < ret; i++) {
3589 			if (!gang[i])
3590 				continue;
3591 			root_objectid = gang[i]->root_key.objectid;
3592 			err = btrfs_orphan_cleanup(gang[i]);
3593 			if (err)
3594 				break;
3595 			btrfs_put_fs_root(gang[i]);
3596 		}
3597 		root_objectid++;
3598 	}
3599 
3600 	/* release the uncleaned roots due to error */
3601 	for (; i < ret; i++) {
3602 		if (gang[i])
3603 			btrfs_put_fs_root(gang[i]);
3604 	}
3605 	return err;
3606 }
3607 
3608 int btrfs_commit_super(struct btrfs_root *root)
3609 {
3610 	struct btrfs_trans_handle *trans;
3611 
3612 	mutex_lock(&root->fs_info->cleaner_mutex);
3613 	btrfs_run_delayed_iputs(root);
3614 	mutex_unlock(&root->fs_info->cleaner_mutex);
3615 	wake_up_process(root->fs_info->cleaner_kthread);
3616 
3617 	/* wait until ongoing cleanup work done */
3618 	down_write(&root->fs_info->cleanup_work_sem);
3619 	up_write(&root->fs_info->cleanup_work_sem);
3620 
3621 	trans = btrfs_join_transaction(root);
3622 	if (IS_ERR(trans))
3623 		return PTR_ERR(trans);
3624 	return btrfs_commit_transaction(trans, root);
3625 }
3626 
3627 void close_ctree(struct btrfs_root *root)
3628 {
3629 	struct btrfs_fs_info *fs_info = root->fs_info;
3630 	int ret;
3631 
3632 	fs_info->closing = 1;
3633 	smp_mb();
3634 
3635 	/* wait for the uuid_scan task to finish */
3636 	down(&fs_info->uuid_tree_rescan_sem);
3637 	/* avoid complains from lockdep et al., set sem back to initial state */
3638 	up(&fs_info->uuid_tree_rescan_sem);
3639 
3640 	/* pause restriper - we want to resume on mount */
3641 	btrfs_pause_balance(fs_info);
3642 
3643 	btrfs_dev_replace_suspend_for_unmount(fs_info);
3644 
3645 	btrfs_scrub_cancel(fs_info);
3646 
3647 	/* wait for any defraggers to finish */
3648 	wait_event(fs_info->transaction_wait,
3649 		   (atomic_read(&fs_info->defrag_running) == 0));
3650 
3651 	/* clear out the rbtree of defraggable inodes */
3652 	btrfs_cleanup_defrag_inodes(fs_info);
3653 
3654 	cancel_work_sync(&fs_info->async_reclaim_work);
3655 
3656 	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3657 		ret = btrfs_commit_super(root);
3658 		if (ret)
3659 			btrfs_err(root->fs_info, "commit super ret %d", ret);
3660 	}
3661 
3662 	if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
3663 		btrfs_error_commit_super(root);
3664 
3665 	kthread_stop(fs_info->transaction_kthread);
3666 	kthread_stop(fs_info->cleaner_kthread);
3667 
3668 	fs_info->closing = 2;
3669 	smp_mb();
3670 
3671 	btrfs_free_qgroup_config(root->fs_info);
3672 
3673 	if (percpu_counter_sum(&fs_info->delalloc_bytes)) {
3674 		btrfs_info(root->fs_info, "at unmount delalloc count %lld",
3675 		       percpu_counter_sum(&fs_info->delalloc_bytes));
3676 	}
3677 
3678 	btrfs_sysfs_remove_one(fs_info);
3679 
3680 	btrfs_free_fs_roots(fs_info);
3681 
3682 	btrfs_put_block_group_cache(fs_info);
3683 
3684 	btrfs_free_block_groups(fs_info);
3685 
3686 	/*
3687 	 * we must make sure there is not any read request to
3688 	 * submit after we stopping all workers.
3689 	 */
3690 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
3691 	btrfs_stop_all_workers(fs_info);
3692 
3693 	fs_info->open = 0;
3694 	free_root_pointers(fs_info, 1);
3695 
3696 	iput(fs_info->btree_inode);
3697 
3698 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3699 	if (btrfs_test_opt(root, CHECK_INTEGRITY))
3700 		btrfsic_unmount(root, fs_info->fs_devices);
3701 #endif
3702 
3703 	btrfs_close_devices(fs_info->fs_devices);
3704 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
3705 
3706 	percpu_counter_destroy(&fs_info->dirty_metadata_bytes);
3707 	percpu_counter_destroy(&fs_info->delalloc_bytes);
3708 	percpu_counter_destroy(&fs_info->bio_counter);
3709 	bdi_destroy(&fs_info->bdi);
3710 	cleanup_srcu_struct(&fs_info->subvol_srcu);
3711 
3712 	btrfs_free_stripe_hash_table(fs_info);
3713 
3714 	btrfs_free_block_rsv(root, root->orphan_block_rsv);
3715 	root->orphan_block_rsv = NULL;
3716 }
3717 
3718 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid,
3719 			  int atomic)
3720 {
3721 	int ret;
3722 	struct inode *btree_inode = buf->pages[0]->mapping->host;
3723 
3724 	ret = extent_buffer_uptodate(buf);
3725 	if (!ret)
3726 		return ret;
3727 
3728 	ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3729 				    parent_transid, atomic);
3730 	if (ret == -EAGAIN)
3731 		return ret;
3732 	return !ret;
3733 }
3734 
3735 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3736 {
3737 	return set_extent_buffer_uptodate(buf);
3738 }
3739 
3740 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3741 {
3742 	struct btrfs_root *root;
3743 	u64 transid = btrfs_header_generation(buf);
3744 	int was_dirty;
3745 
3746 #ifdef CONFIG_BTRFS_FS_RUN_SANITY_TESTS
3747 	/*
3748 	 * This is a fast path so only do this check if we have sanity tests
3749 	 * enabled.  Normal people shouldn't be marking dummy buffers as dirty
3750 	 * outside of the sanity tests.
3751 	 */
3752 	if (unlikely(test_bit(EXTENT_BUFFER_DUMMY, &buf->bflags)))
3753 		return;
3754 #endif
3755 	root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3756 	btrfs_assert_tree_locked(buf);
3757 	if (transid != root->fs_info->generation)
3758 		WARN(1, KERN_CRIT "btrfs transid mismatch buffer %llu, "
3759 		       "found %llu running %llu\n",
3760 			buf->start, transid, root->fs_info->generation);
3761 	was_dirty = set_extent_buffer_dirty(buf);
3762 	if (!was_dirty)
3763 		__percpu_counter_add(&root->fs_info->dirty_metadata_bytes,
3764 				     buf->len,
3765 				     root->fs_info->dirty_metadata_batch);
3766 #ifdef CONFIG_BTRFS_FS_CHECK_INTEGRITY
3767 	if (btrfs_header_level(buf) == 0 && check_leaf(root, buf)) {
3768 		btrfs_print_leaf(root, buf);
3769 		ASSERT(0);
3770 	}
3771 #endif
3772 }
3773 
3774 static void __btrfs_btree_balance_dirty(struct btrfs_root *root,
3775 					int flush_delayed)
3776 {
3777 	/*
3778 	 * looks as though older kernels can get into trouble with
3779 	 * this code, they end up stuck in balance_dirty_pages forever
3780 	 */
3781 	int ret;
3782 
3783 	if (current->flags & PF_MEMALLOC)
3784 		return;
3785 
3786 	if (flush_delayed)
3787 		btrfs_balance_delayed_items(root);
3788 
3789 	ret = percpu_counter_compare(&root->fs_info->dirty_metadata_bytes,
3790 				     BTRFS_DIRTY_METADATA_THRESH);
3791 	if (ret > 0) {
3792 		balance_dirty_pages_ratelimited(
3793 				   root->fs_info->btree_inode->i_mapping);
3794 	}
3795 	return;
3796 }
3797 
3798 void btrfs_btree_balance_dirty(struct btrfs_root *root)
3799 {
3800 	__btrfs_btree_balance_dirty(root, 1);
3801 }
3802 
3803 void btrfs_btree_balance_dirty_nodelay(struct btrfs_root *root)
3804 {
3805 	__btrfs_btree_balance_dirty(root, 0);
3806 }
3807 
3808 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3809 {
3810 	struct btrfs_root *root = BTRFS_I(buf->pages[0]->mapping->host)->root;
3811 	return btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3812 }
3813 
3814 static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3815 			      int read_only)
3816 {
3817 	struct btrfs_super_block *sb = fs_info->super_copy;
3818 	int ret = 0;
3819 
3820 	if (btrfs_super_root_level(sb) >= BTRFS_MAX_LEVEL) {
3821 		printk(KERN_ERR "BTRFS: tree_root level too big: %d >= %d\n",
3822 				btrfs_super_root_level(sb), BTRFS_MAX_LEVEL);
3823 		ret = -EINVAL;
3824 	}
3825 	if (btrfs_super_chunk_root_level(sb) >= BTRFS_MAX_LEVEL) {
3826 		printk(KERN_ERR "BTRFS: chunk_root level too big: %d >= %d\n",
3827 				btrfs_super_chunk_root_level(sb), BTRFS_MAX_LEVEL);
3828 		ret = -EINVAL;
3829 	}
3830 	if (btrfs_super_log_root_level(sb) >= BTRFS_MAX_LEVEL) {
3831 		printk(KERN_ERR "BTRFS: log_root level too big: %d >= %d\n",
3832 				btrfs_super_log_root_level(sb), BTRFS_MAX_LEVEL);
3833 		ret = -EINVAL;
3834 	}
3835 
3836 	/*
3837 	 * The common minimum, we don't know if we can trust the nodesize/sectorsize
3838 	 * items yet, they'll be verified later. Issue just a warning.
3839 	 */
3840 	if (!IS_ALIGNED(btrfs_super_root(sb), 4096))
3841 		printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3842 				sb->root);
3843 	if (!IS_ALIGNED(btrfs_super_chunk_root(sb), 4096))
3844 		printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3845 				sb->chunk_root);
3846 	if (!IS_ALIGNED(btrfs_super_log_root(sb), 4096))
3847 		printk(KERN_WARNING "BTRFS: tree_root block unaligned: %llu\n",
3848 				btrfs_super_log_root(sb));
3849 
3850 	if (memcmp(fs_info->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) {
3851 		printk(KERN_ERR "BTRFS: dev_item UUID does not match fsid: %pU != %pU\n",
3852 				fs_info->fsid, sb->dev_item.fsid);
3853 		ret = -EINVAL;
3854 	}
3855 
3856 	/*
3857 	 * Hint to catch really bogus numbers, bitflips or so, more exact checks are
3858 	 * done later
3859 	 */
3860 	if (btrfs_super_num_devices(sb) > (1UL << 31))
3861 		printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n",
3862 				btrfs_super_num_devices(sb));
3863 
3864 	if (btrfs_super_bytenr(sb) != BTRFS_SUPER_INFO_OFFSET) {
3865 		printk(KERN_ERR "BTRFS: super offset mismatch %llu != %u\n",
3866 				btrfs_super_bytenr(sb), BTRFS_SUPER_INFO_OFFSET);
3867 		ret = -EINVAL;
3868 	}
3869 
3870 	/*
3871 	 * The generation is a global counter, we'll trust it more than the others
3872 	 * but it's still possible that it's the one that's wrong.
3873 	 */
3874 	if (btrfs_super_generation(sb) < btrfs_super_chunk_root_generation(sb))
3875 		printk(KERN_WARNING
3876 			"BTRFS: suspicious: generation < chunk_root_generation: %llu < %llu\n",
3877 			btrfs_super_generation(sb), btrfs_super_chunk_root_generation(sb));
3878 	if (btrfs_super_generation(sb) < btrfs_super_cache_generation(sb)
3879 	    && btrfs_super_cache_generation(sb) != (u64)-1)
3880 		printk(KERN_WARNING
3881 			"BTRFS: suspicious: generation < cache_generation: %llu < %llu\n",
3882 			btrfs_super_generation(sb), btrfs_super_cache_generation(sb));
3883 
3884 	return ret;
3885 }
3886 
3887 static void btrfs_error_commit_super(struct btrfs_root *root)
3888 {
3889 	mutex_lock(&root->fs_info->cleaner_mutex);
3890 	btrfs_run_delayed_iputs(root);
3891 	mutex_unlock(&root->fs_info->cleaner_mutex);
3892 
3893 	down_write(&root->fs_info->cleanup_work_sem);
3894 	up_write(&root->fs_info->cleanup_work_sem);
3895 
3896 	/* cleanup FS via transaction */
3897 	btrfs_cleanup_transaction(root);
3898 }
3899 
3900 static void btrfs_destroy_ordered_extents(struct btrfs_root *root)
3901 {
3902 	struct btrfs_ordered_extent *ordered;
3903 
3904 	spin_lock(&root->ordered_extent_lock);
3905 	/*
3906 	 * This will just short circuit the ordered completion stuff which will
3907 	 * make sure the ordered extent gets properly cleaned up.
3908 	 */
3909 	list_for_each_entry(ordered, &root->ordered_extents,
3910 			    root_extent_list)
3911 		set_bit(BTRFS_ORDERED_IOERR, &ordered->flags);
3912 	spin_unlock(&root->ordered_extent_lock);
3913 }
3914 
3915 static void btrfs_destroy_all_ordered_extents(struct btrfs_fs_info *fs_info)
3916 {
3917 	struct btrfs_root *root;
3918 	struct list_head splice;
3919 
3920 	INIT_LIST_HEAD(&splice);
3921 
3922 	spin_lock(&fs_info->ordered_root_lock);
3923 	list_splice_init(&fs_info->ordered_roots, &splice);
3924 	while (!list_empty(&splice)) {
3925 		root = list_first_entry(&splice, struct btrfs_root,
3926 					ordered_root);
3927 		list_move_tail(&root->ordered_root,
3928 			       &fs_info->ordered_roots);
3929 
3930 		spin_unlock(&fs_info->ordered_root_lock);
3931 		btrfs_destroy_ordered_extents(root);
3932 
3933 		cond_resched();
3934 		spin_lock(&fs_info->ordered_root_lock);
3935 	}
3936 	spin_unlock(&fs_info->ordered_root_lock);
3937 }
3938 
3939 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3940 				      struct btrfs_root *root)
3941 {
3942 	struct rb_node *node;
3943 	struct btrfs_delayed_ref_root *delayed_refs;
3944 	struct btrfs_delayed_ref_node *ref;
3945 	int ret = 0;
3946 
3947 	delayed_refs = &trans->delayed_refs;
3948 
3949 	spin_lock(&delayed_refs->lock);
3950 	if (atomic_read(&delayed_refs->num_entries) == 0) {
3951 		spin_unlock(&delayed_refs->lock);
3952 		btrfs_info(root->fs_info, "delayed_refs has NO entry");
3953 		return ret;
3954 	}
3955 
3956 	while ((node = rb_first(&delayed_refs->href_root)) != NULL) {
3957 		struct btrfs_delayed_ref_head *head;
3958 		bool pin_bytes = false;
3959 
3960 		head = rb_entry(node, struct btrfs_delayed_ref_head,
3961 				href_node);
3962 		if (!mutex_trylock(&head->mutex)) {
3963 			atomic_inc(&head->node.refs);
3964 			spin_unlock(&delayed_refs->lock);
3965 
3966 			mutex_lock(&head->mutex);
3967 			mutex_unlock(&head->mutex);
3968 			btrfs_put_delayed_ref(&head->node);
3969 			spin_lock(&delayed_refs->lock);
3970 			continue;
3971 		}
3972 		spin_lock(&head->lock);
3973 		while ((node = rb_first(&head->ref_root)) != NULL) {
3974 			ref = rb_entry(node, struct btrfs_delayed_ref_node,
3975 				       rb_node);
3976 			ref->in_tree = 0;
3977 			rb_erase(&ref->rb_node, &head->ref_root);
3978 			atomic_dec(&delayed_refs->num_entries);
3979 			btrfs_put_delayed_ref(ref);
3980 		}
3981 		if (head->must_insert_reserved)
3982 			pin_bytes = true;
3983 		btrfs_free_delayed_extent_op(head->extent_op);
3984 		delayed_refs->num_heads--;
3985 		if (head->processing == 0)
3986 			delayed_refs->num_heads_ready--;
3987 		atomic_dec(&delayed_refs->num_entries);
3988 		head->node.in_tree = 0;
3989 		rb_erase(&head->href_node, &delayed_refs->href_root);
3990 		spin_unlock(&head->lock);
3991 		spin_unlock(&delayed_refs->lock);
3992 		mutex_unlock(&head->mutex);
3993 
3994 		if (pin_bytes)
3995 			btrfs_pin_extent(root, head->node.bytenr,
3996 					 head->node.num_bytes, 1);
3997 		btrfs_put_delayed_ref(&head->node);
3998 		cond_resched();
3999 		spin_lock(&delayed_refs->lock);
4000 	}
4001 
4002 	spin_unlock(&delayed_refs->lock);
4003 
4004 	return ret;
4005 }
4006 
4007 static void btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
4008 {
4009 	struct btrfs_inode *btrfs_inode;
4010 	struct list_head splice;
4011 
4012 	INIT_LIST_HEAD(&splice);
4013 
4014 	spin_lock(&root->delalloc_lock);
4015 	list_splice_init(&root->delalloc_inodes, &splice);
4016 
4017 	while (!list_empty(&splice)) {
4018 		btrfs_inode = list_first_entry(&splice, struct btrfs_inode,
4019 					       delalloc_inodes);
4020 
4021 		list_del_init(&btrfs_inode->delalloc_inodes);
4022 		clear_bit(BTRFS_INODE_IN_DELALLOC_LIST,
4023 			  &btrfs_inode->runtime_flags);
4024 		spin_unlock(&root->delalloc_lock);
4025 
4026 		btrfs_invalidate_inodes(btrfs_inode->root);
4027 
4028 		spin_lock(&root->delalloc_lock);
4029 	}
4030 
4031 	spin_unlock(&root->delalloc_lock);
4032 }
4033 
4034 static void btrfs_destroy_all_delalloc_inodes(struct btrfs_fs_info *fs_info)
4035 {
4036 	struct btrfs_root *root;
4037 	struct list_head splice;
4038 
4039 	INIT_LIST_HEAD(&splice);
4040 
4041 	spin_lock(&fs_info->delalloc_root_lock);
4042 	list_splice_init(&fs_info->delalloc_roots, &splice);
4043 	while (!list_empty(&splice)) {
4044 		root = list_first_entry(&splice, struct btrfs_root,
4045 					 delalloc_root);
4046 		list_del_init(&root->delalloc_root);
4047 		root = btrfs_grab_fs_root(root);
4048 		BUG_ON(!root);
4049 		spin_unlock(&fs_info->delalloc_root_lock);
4050 
4051 		btrfs_destroy_delalloc_inodes(root);
4052 		btrfs_put_fs_root(root);
4053 
4054 		spin_lock(&fs_info->delalloc_root_lock);
4055 	}
4056 	spin_unlock(&fs_info->delalloc_root_lock);
4057 }
4058 
4059 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
4060 					struct extent_io_tree *dirty_pages,
4061 					int mark)
4062 {
4063 	int ret;
4064 	struct extent_buffer *eb;
4065 	u64 start = 0;
4066 	u64 end;
4067 
4068 	while (1) {
4069 		ret = find_first_extent_bit(dirty_pages, start, &start, &end,
4070 					    mark, NULL);
4071 		if (ret)
4072 			break;
4073 
4074 		clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
4075 		while (start <= end) {
4076 			eb = btrfs_find_tree_block(root, start);
4077 			start += root->nodesize;
4078 			if (!eb)
4079 				continue;
4080 			wait_on_extent_buffer_writeback(eb);
4081 
4082 			if (test_and_clear_bit(EXTENT_BUFFER_DIRTY,
4083 					       &eb->bflags))
4084 				clear_extent_buffer_dirty(eb);
4085 			free_extent_buffer_stale(eb);
4086 		}
4087 	}
4088 
4089 	return ret;
4090 }
4091 
4092 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
4093 				       struct extent_io_tree *pinned_extents)
4094 {
4095 	struct extent_io_tree *unpin;
4096 	u64 start;
4097 	u64 end;
4098 	int ret;
4099 	bool loop = true;
4100 
4101 	unpin = pinned_extents;
4102 again:
4103 	while (1) {
4104 		ret = find_first_extent_bit(unpin, 0, &start, &end,
4105 					    EXTENT_DIRTY, NULL);
4106 		if (ret)
4107 			break;
4108 
4109 		/* opt_discard */
4110 		if (btrfs_test_opt(root, DISCARD))
4111 			ret = btrfs_error_discard_extent(root, start,
4112 							 end + 1 - start,
4113 							 NULL);
4114 
4115 		clear_extent_dirty(unpin, start, end, GFP_NOFS);
4116 		btrfs_error_unpin_extent_range(root, start, end);
4117 		cond_resched();
4118 	}
4119 
4120 	if (loop) {
4121 		if (unpin == &root->fs_info->freed_extents[0])
4122 			unpin = &root->fs_info->freed_extents[1];
4123 		else
4124 			unpin = &root->fs_info->freed_extents[0];
4125 		loop = false;
4126 		goto again;
4127 	}
4128 
4129 	return 0;
4130 }
4131 
4132 void btrfs_cleanup_one_transaction(struct btrfs_transaction *cur_trans,
4133 				   struct btrfs_root *root)
4134 {
4135 	btrfs_destroy_delayed_refs(cur_trans, root);
4136 
4137 	cur_trans->state = TRANS_STATE_COMMIT_START;
4138 	wake_up(&root->fs_info->transaction_blocked_wait);
4139 
4140 	cur_trans->state = TRANS_STATE_UNBLOCKED;
4141 	wake_up(&root->fs_info->transaction_wait);
4142 
4143 	btrfs_destroy_delayed_inodes(root);
4144 	btrfs_assert_delayed_root_empty(root);
4145 
4146 	btrfs_destroy_marked_extents(root, &cur_trans->dirty_pages,
4147 				     EXTENT_DIRTY);
4148 	btrfs_destroy_pinned_extent(root,
4149 				    root->fs_info->pinned_extents);
4150 
4151 	cur_trans->state =TRANS_STATE_COMPLETED;
4152 	wake_up(&cur_trans->commit_wait);
4153 
4154 	/*
4155 	memset(cur_trans, 0, sizeof(*cur_trans));
4156 	kmem_cache_free(btrfs_transaction_cachep, cur_trans);
4157 	*/
4158 }
4159 
4160 static int btrfs_cleanup_transaction(struct btrfs_root *root)
4161 {
4162 	struct btrfs_transaction *t;
4163 
4164 	mutex_lock(&root->fs_info->transaction_kthread_mutex);
4165 
4166 	spin_lock(&root->fs_info->trans_lock);
4167 	while (!list_empty(&root->fs_info->trans_list)) {
4168 		t = list_first_entry(&root->fs_info->trans_list,
4169 				     struct btrfs_transaction, list);
4170 		if (t->state >= TRANS_STATE_COMMIT_START) {
4171 			atomic_inc(&t->use_count);
4172 			spin_unlock(&root->fs_info->trans_lock);
4173 			btrfs_wait_for_commit(root, t->transid);
4174 			btrfs_put_transaction(t);
4175 			spin_lock(&root->fs_info->trans_lock);
4176 			continue;
4177 		}
4178 		if (t == root->fs_info->running_transaction) {
4179 			t->state = TRANS_STATE_COMMIT_DOING;
4180 			spin_unlock(&root->fs_info->trans_lock);
4181 			/*
4182 			 * We wait for 0 num_writers since we don't hold a trans
4183 			 * handle open currently for this transaction.
4184 			 */
4185 			wait_event(t->writer_wait,
4186 				   atomic_read(&t->num_writers) == 0);
4187 		} else {
4188 			spin_unlock(&root->fs_info->trans_lock);
4189 		}
4190 		btrfs_cleanup_one_transaction(t, root);
4191 
4192 		spin_lock(&root->fs_info->trans_lock);
4193 		if (t == root->fs_info->running_transaction)
4194 			root->fs_info->running_transaction = NULL;
4195 		list_del_init(&t->list);
4196 		spin_unlock(&root->fs_info->trans_lock);
4197 
4198 		btrfs_put_transaction(t);
4199 		trace_btrfs_transaction_commit(root);
4200 		spin_lock(&root->fs_info->trans_lock);
4201 	}
4202 	spin_unlock(&root->fs_info->trans_lock);
4203 	btrfs_destroy_all_ordered_extents(root->fs_info);
4204 	btrfs_destroy_delayed_inodes(root);
4205 	btrfs_assert_delayed_root_empty(root);
4206 	btrfs_destroy_pinned_extent(root, root->fs_info->pinned_extents);
4207 	btrfs_destroy_all_delalloc_inodes(root->fs_info);
4208 	mutex_unlock(&root->fs_info->transaction_kthread_mutex);
4209 
4210 	return 0;
4211 }
4212 
4213 static struct extent_io_ops btree_extent_io_ops = {
4214 	.readpage_end_io_hook = btree_readpage_end_io_hook,
4215 	.readpage_io_failed_hook = btree_io_failed_hook,
4216 	.submit_bio_hook = btree_submit_bio_hook,
4217 	/* note we're sharing with inode.c for the merge bio hook */
4218 	.merge_bio_hook = btrfs_merge_bio_hook,
4219 };
4220