xref: /linux/fs/btrfs/disk-io.c (revision 12871a0bd67dd4db4418e1daafcd46e9d329ef10)
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/crc32c.h>
30 #include <linux/slab.h>
31 #include <linux/migrate.h>
32 #include <linux/ratelimit.h>
33 #include <asm/unaligned.h>
34 #include "compat.h"
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "volumes.h"
40 #include "print-tree.h"
41 #include "async-thread.h"
42 #include "locking.h"
43 #include "tree-log.h"
44 #include "free-space-cache.h"
45 #include "inode-map.h"
46 
47 static struct extent_io_ops btree_extent_io_ops;
48 static void end_workqueue_fn(struct btrfs_work *work);
49 static void free_fs_root(struct btrfs_root *root);
50 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
51 				    int read_only);
52 static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
53 static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
54 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
55 				      struct btrfs_root *root);
56 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
57 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
58 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
59 					struct extent_io_tree *dirty_pages,
60 					int mark);
61 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
62 				       struct extent_io_tree *pinned_extents);
63 static int btrfs_cleanup_transaction(struct btrfs_root *root);
64 
65 /*
66  * end_io_wq structs are used to do processing in task context when an IO is
67  * complete.  This is used during reads to verify checksums, and it is used
68  * by writes to insert metadata for new file extents after IO is complete.
69  */
70 struct end_io_wq {
71 	struct bio *bio;
72 	bio_end_io_t *end_io;
73 	void *private;
74 	struct btrfs_fs_info *info;
75 	int error;
76 	int metadata;
77 	struct list_head list;
78 	struct btrfs_work work;
79 };
80 
81 /*
82  * async submit bios are used to offload expensive checksumming
83  * onto the worker threads.  They checksum file and metadata bios
84  * just before they are sent down the IO stack.
85  */
86 struct async_submit_bio {
87 	struct inode *inode;
88 	struct bio *bio;
89 	struct list_head list;
90 	extent_submit_bio_hook_t *submit_bio_start;
91 	extent_submit_bio_hook_t *submit_bio_done;
92 	int rw;
93 	int mirror_num;
94 	unsigned long bio_flags;
95 	/*
96 	 * bio_offset is optional, can be used if the pages in the bio
97 	 * can't tell us where in the file the bio should go
98 	 */
99 	u64 bio_offset;
100 	struct btrfs_work work;
101 };
102 
103 /* These are used to set the lockdep class on the extent buffer locks.
104  * The class is set by the readpage_end_io_hook after the buffer has
105  * passed csum validation but before the pages are unlocked.
106  *
107  * The lockdep class is also set by btrfs_init_new_buffer on freshly
108  * allocated blocks.
109  *
110  * The class is based on the level in the tree block, which allows lockdep
111  * to know that lower nodes nest inside the locks of higher nodes.
112  *
113  * We also add a check to make sure the highest level of the tree is
114  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
115  * code needs update as well.
116  */
117 #ifdef CONFIG_DEBUG_LOCK_ALLOC
118 # if BTRFS_MAX_LEVEL != 8
119 #  error
120 # endif
121 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
122 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
123 	/* leaf */
124 	"btrfs-extent-00",
125 	"btrfs-extent-01",
126 	"btrfs-extent-02",
127 	"btrfs-extent-03",
128 	"btrfs-extent-04",
129 	"btrfs-extent-05",
130 	"btrfs-extent-06",
131 	"btrfs-extent-07",
132 	/* highest possible level */
133 	"btrfs-extent-08",
134 };
135 #endif
136 
137 /*
138  * extents on the btree inode are pretty simple, there's one extent
139  * that covers the entire device
140  */
141 static struct extent_map *btree_get_extent(struct inode *inode,
142 		struct page *page, size_t pg_offset, u64 start, u64 len,
143 		int create)
144 {
145 	struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
146 	struct extent_map *em;
147 	int ret;
148 
149 	read_lock(&em_tree->lock);
150 	em = lookup_extent_mapping(em_tree, start, len);
151 	if (em) {
152 		em->bdev =
153 			BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
154 		read_unlock(&em_tree->lock);
155 		goto out;
156 	}
157 	read_unlock(&em_tree->lock);
158 
159 	em = alloc_extent_map();
160 	if (!em) {
161 		em = ERR_PTR(-ENOMEM);
162 		goto out;
163 	}
164 	em->start = 0;
165 	em->len = (u64)-1;
166 	em->block_len = (u64)-1;
167 	em->block_start = 0;
168 	em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
169 
170 	write_lock(&em_tree->lock);
171 	ret = add_extent_mapping(em_tree, em);
172 	if (ret == -EEXIST) {
173 		u64 failed_start = em->start;
174 		u64 failed_len = em->len;
175 
176 		free_extent_map(em);
177 		em = lookup_extent_mapping(em_tree, start, len);
178 		if (em) {
179 			ret = 0;
180 		} else {
181 			em = lookup_extent_mapping(em_tree, failed_start,
182 						   failed_len);
183 			ret = -EIO;
184 		}
185 	} else if (ret) {
186 		free_extent_map(em);
187 		em = NULL;
188 	}
189 	write_unlock(&em_tree->lock);
190 
191 	if (ret)
192 		em = ERR_PTR(ret);
193 out:
194 	return em;
195 }
196 
197 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
198 {
199 	return crc32c(seed, data, len);
200 }
201 
202 void btrfs_csum_final(u32 crc, char *result)
203 {
204 	put_unaligned_le32(~crc, result);
205 }
206 
207 /*
208  * compute the csum for a btree block, and either verify it or write it
209  * into the csum field of the block.
210  */
211 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
212 			   int verify)
213 {
214 	u16 csum_size =
215 		btrfs_super_csum_size(&root->fs_info->super_copy);
216 	char *result = NULL;
217 	unsigned long len;
218 	unsigned long cur_len;
219 	unsigned long offset = BTRFS_CSUM_SIZE;
220 	char *map_token = NULL;
221 	char *kaddr;
222 	unsigned long map_start;
223 	unsigned long map_len;
224 	int err;
225 	u32 crc = ~(u32)0;
226 	unsigned long inline_result;
227 
228 	len = buf->len - offset;
229 	while (len > 0) {
230 		err = map_private_extent_buffer(buf, offset, 32,
231 					&map_token, &kaddr,
232 					&map_start, &map_len, KM_USER0);
233 		if (err)
234 			return 1;
235 		cur_len = min(len, map_len - (offset - map_start));
236 		crc = btrfs_csum_data(root, kaddr + offset - map_start,
237 				      crc, cur_len);
238 		len -= cur_len;
239 		offset += cur_len;
240 		unmap_extent_buffer(buf, map_token, KM_USER0);
241 	}
242 	if (csum_size > sizeof(inline_result)) {
243 		result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
244 		if (!result)
245 			return 1;
246 	} else {
247 		result = (char *)&inline_result;
248 	}
249 
250 	btrfs_csum_final(crc, result);
251 
252 	if (verify) {
253 		if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
254 			u32 val;
255 			u32 found = 0;
256 			memcpy(&found, result, csum_size);
257 
258 			read_extent_buffer(buf, &val, 0, csum_size);
259 			printk_ratelimited(KERN_INFO "btrfs: %s checksum verify "
260 				       "failed on %llu wanted %X found %X "
261 				       "level %d\n",
262 				       root->fs_info->sb->s_id,
263 				       (unsigned long long)buf->start, val, found,
264 				       btrfs_header_level(buf));
265 			if (result != (char *)&inline_result)
266 				kfree(result);
267 			return 1;
268 		}
269 	} else {
270 		write_extent_buffer(buf, result, 0, csum_size);
271 	}
272 	if (result != (char *)&inline_result)
273 		kfree(result);
274 	return 0;
275 }
276 
277 /*
278  * we can't consider a given block up to date unless the transid of the
279  * block matches the transid in the parent node's pointer.  This is how we
280  * detect blocks that either didn't get written at all or got written
281  * in the wrong place.
282  */
283 static int verify_parent_transid(struct extent_io_tree *io_tree,
284 				 struct extent_buffer *eb, u64 parent_transid)
285 {
286 	struct extent_state *cached_state = NULL;
287 	int ret;
288 
289 	if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
290 		return 0;
291 
292 	lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
293 			 0, &cached_state, GFP_NOFS);
294 	if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
295 	    btrfs_header_generation(eb) == parent_transid) {
296 		ret = 0;
297 		goto out;
298 	}
299 	printk_ratelimited("parent transid verify failed on %llu wanted %llu "
300 		       "found %llu\n",
301 		       (unsigned long long)eb->start,
302 		       (unsigned long long)parent_transid,
303 		       (unsigned long long)btrfs_header_generation(eb));
304 	ret = 1;
305 	clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
306 out:
307 	unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
308 			     &cached_state, GFP_NOFS);
309 	return ret;
310 }
311 
312 /*
313  * helper to read a given tree block, doing retries as required when
314  * the checksums don't match and we have alternate mirrors to try.
315  */
316 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
317 					  struct extent_buffer *eb,
318 					  u64 start, u64 parent_transid)
319 {
320 	struct extent_io_tree *io_tree;
321 	int ret;
322 	int num_copies = 0;
323 	int mirror_num = 0;
324 
325 	clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
326 	io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
327 	while (1) {
328 		ret = read_extent_buffer_pages(io_tree, eb, start, 1,
329 					       btree_get_extent, mirror_num);
330 		if (!ret &&
331 		    !verify_parent_transid(io_tree, eb, parent_transid))
332 			return ret;
333 
334 		/*
335 		 * This buffer's crc is fine, but its contents are corrupted, so
336 		 * there is no reason to read the other copies, they won't be
337 		 * any less wrong.
338 		 */
339 		if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
340 			return ret;
341 
342 		num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
343 					      eb->start, eb->len);
344 		if (num_copies == 1)
345 			return ret;
346 
347 		mirror_num++;
348 		if (mirror_num > num_copies)
349 			return ret;
350 	}
351 	return -EIO;
352 }
353 
354 /*
355  * checksum a dirty tree block before IO.  This has extra checks to make sure
356  * we only fill in the checksum field in the first page of a multi-page block
357  */
358 
359 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
360 {
361 	struct extent_io_tree *tree;
362 	u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
363 	u64 found_start;
364 	unsigned long len;
365 	struct extent_buffer *eb;
366 	int ret;
367 
368 	tree = &BTRFS_I(page->mapping->host)->io_tree;
369 
370 	if (page->private == EXTENT_PAGE_PRIVATE) {
371 		WARN_ON(1);
372 		goto out;
373 	}
374 	if (!page->private) {
375 		WARN_ON(1);
376 		goto out;
377 	}
378 	len = page->private >> 2;
379 	WARN_ON(len == 0);
380 
381 	eb = alloc_extent_buffer(tree, start, len, page);
382 	if (eb == NULL) {
383 		WARN_ON(1);
384 		goto out;
385 	}
386 	ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
387 					     btrfs_header_generation(eb));
388 	BUG_ON(ret);
389 	WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
390 
391 	found_start = btrfs_header_bytenr(eb);
392 	if (found_start != start) {
393 		WARN_ON(1);
394 		goto err;
395 	}
396 	if (eb->first_page != page) {
397 		WARN_ON(1);
398 		goto err;
399 	}
400 	if (!PageUptodate(page)) {
401 		WARN_ON(1);
402 		goto err;
403 	}
404 	csum_tree_block(root, eb, 0);
405 err:
406 	free_extent_buffer(eb);
407 out:
408 	return 0;
409 }
410 
411 static int check_tree_block_fsid(struct btrfs_root *root,
412 				 struct extent_buffer *eb)
413 {
414 	struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
415 	u8 fsid[BTRFS_UUID_SIZE];
416 	int ret = 1;
417 
418 	read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
419 			   BTRFS_FSID_SIZE);
420 	while (fs_devices) {
421 		if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
422 			ret = 0;
423 			break;
424 		}
425 		fs_devices = fs_devices->seed;
426 	}
427 	return ret;
428 }
429 
430 #define CORRUPT(reason, eb, root, slot)				\
431 	printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu,"	\
432 	       "root=%llu, slot=%d\n", reason,			\
433 	       (unsigned long long)btrfs_header_bytenr(eb),	\
434 	       (unsigned long long)root->objectid, slot)
435 
436 static noinline int check_leaf(struct btrfs_root *root,
437 			       struct extent_buffer *leaf)
438 {
439 	struct btrfs_key key;
440 	struct btrfs_key leaf_key;
441 	u32 nritems = btrfs_header_nritems(leaf);
442 	int slot;
443 
444 	if (nritems == 0)
445 		return 0;
446 
447 	/* Check the 0 item */
448 	if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
449 	    BTRFS_LEAF_DATA_SIZE(root)) {
450 		CORRUPT("invalid item offset size pair", leaf, root, 0);
451 		return -EIO;
452 	}
453 
454 	/*
455 	 * Check to make sure each items keys are in the correct order and their
456 	 * offsets make sense.  We only have to loop through nritems-1 because
457 	 * we check the current slot against the next slot, which verifies the
458 	 * next slot's offset+size makes sense and that the current's slot
459 	 * offset is correct.
460 	 */
461 	for (slot = 0; slot < nritems - 1; slot++) {
462 		btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
463 		btrfs_item_key_to_cpu(leaf, &key, slot + 1);
464 
465 		/* Make sure the keys are in the right order */
466 		if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
467 			CORRUPT("bad key order", leaf, root, slot);
468 			return -EIO;
469 		}
470 
471 		/*
472 		 * Make sure the offset and ends are right, remember that the
473 		 * item data starts at the end of the leaf and grows towards the
474 		 * front.
475 		 */
476 		if (btrfs_item_offset_nr(leaf, slot) !=
477 			btrfs_item_end_nr(leaf, slot + 1)) {
478 			CORRUPT("slot offset bad", leaf, root, slot);
479 			return -EIO;
480 		}
481 
482 		/*
483 		 * Check to make sure that we don't point outside of the leaf,
484 		 * just incase all the items are consistent to eachother, but
485 		 * all point outside of the leaf.
486 		 */
487 		if (btrfs_item_end_nr(leaf, slot) >
488 		    BTRFS_LEAF_DATA_SIZE(root)) {
489 			CORRUPT("slot end outside of leaf", leaf, root, slot);
490 			return -EIO;
491 		}
492 	}
493 
494 	return 0;
495 }
496 
497 #ifdef CONFIG_DEBUG_LOCK_ALLOC
498 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
499 {
500 	lockdep_set_class_and_name(&eb->lock,
501 			   &btrfs_eb_class[level],
502 			   btrfs_eb_name[level]);
503 }
504 #endif
505 
506 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
507 			       struct extent_state *state)
508 {
509 	struct extent_io_tree *tree;
510 	u64 found_start;
511 	int found_level;
512 	unsigned long len;
513 	struct extent_buffer *eb;
514 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
515 	int ret = 0;
516 
517 	tree = &BTRFS_I(page->mapping->host)->io_tree;
518 	if (page->private == EXTENT_PAGE_PRIVATE)
519 		goto out;
520 	if (!page->private)
521 		goto out;
522 
523 	len = page->private >> 2;
524 	WARN_ON(len == 0);
525 
526 	eb = alloc_extent_buffer(tree, start, len, page);
527 	if (eb == NULL) {
528 		ret = -EIO;
529 		goto out;
530 	}
531 
532 	found_start = btrfs_header_bytenr(eb);
533 	if (found_start != start) {
534 		printk_ratelimited(KERN_INFO "btrfs bad tree block start "
535 			       "%llu %llu\n",
536 			       (unsigned long long)found_start,
537 			       (unsigned long long)eb->start);
538 		ret = -EIO;
539 		goto err;
540 	}
541 	if (eb->first_page != page) {
542 		printk(KERN_INFO "btrfs bad first page %lu %lu\n",
543 		       eb->first_page->index, page->index);
544 		WARN_ON(1);
545 		ret = -EIO;
546 		goto err;
547 	}
548 	if (check_tree_block_fsid(root, eb)) {
549 		printk_ratelimited(KERN_INFO "btrfs bad fsid on block %llu\n",
550 			       (unsigned long long)eb->start);
551 		ret = -EIO;
552 		goto err;
553 	}
554 	found_level = btrfs_header_level(eb);
555 
556 	btrfs_set_buffer_lockdep_class(eb, found_level);
557 
558 	ret = csum_tree_block(root, eb, 1);
559 	if (ret) {
560 		ret = -EIO;
561 		goto err;
562 	}
563 
564 	/*
565 	 * If this is a leaf block and it is corrupt, set the corrupt bit so
566 	 * that we don't try and read the other copies of this block, just
567 	 * return -EIO.
568 	 */
569 	if (found_level == 0 && check_leaf(root, eb)) {
570 		set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
571 		ret = -EIO;
572 	}
573 
574 	end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
575 	end = eb->start + end - 1;
576 err:
577 	free_extent_buffer(eb);
578 out:
579 	return ret;
580 }
581 
582 static void end_workqueue_bio(struct bio *bio, int err)
583 {
584 	struct end_io_wq *end_io_wq = bio->bi_private;
585 	struct btrfs_fs_info *fs_info;
586 
587 	fs_info = end_io_wq->info;
588 	end_io_wq->error = err;
589 	end_io_wq->work.func = end_workqueue_fn;
590 	end_io_wq->work.flags = 0;
591 
592 	if (bio->bi_rw & REQ_WRITE) {
593 		if (end_io_wq->metadata == 1)
594 			btrfs_queue_worker(&fs_info->endio_meta_write_workers,
595 					   &end_io_wq->work);
596 		else if (end_io_wq->metadata == 2)
597 			btrfs_queue_worker(&fs_info->endio_freespace_worker,
598 					   &end_io_wq->work);
599 		else
600 			btrfs_queue_worker(&fs_info->endio_write_workers,
601 					   &end_io_wq->work);
602 	} else {
603 		if (end_io_wq->metadata)
604 			btrfs_queue_worker(&fs_info->endio_meta_workers,
605 					   &end_io_wq->work);
606 		else
607 			btrfs_queue_worker(&fs_info->endio_workers,
608 					   &end_io_wq->work);
609 	}
610 }
611 
612 /*
613  * For the metadata arg you want
614  *
615  * 0 - if data
616  * 1 - if normal metadta
617  * 2 - if writing to the free space cache area
618  */
619 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
620 			int metadata)
621 {
622 	struct end_io_wq *end_io_wq;
623 	end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
624 	if (!end_io_wq)
625 		return -ENOMEM;
626 
627 	end_io_wq->private = bio->bi_private;
628 	end_io_wq->end_io = bio->bi_end_io;
629 	end_io_wq->info = info;
630 	end_io_wq->error = 0;
631 	end_io_wq->bio = bio;
632 	end_io_wq->metadata = metadata;
633 
634 	bio->bi_private = end_io_wq;
635 	bio->bi_end_io = end_workqueue_bio;
636 	return 0;
637 }
638 
639 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
640 {
641 	unsigned long limit = min_t(unsigned long,
642 				    info->workers.max_workers,
643 				    info->fs_devices->open_devices);
644 	return 256 * limit;
645 }
646 
647 static void run_one_async_start(struct btrfs_work *work)
648 {
649 	struct async_submit_bio *async;
650 
651 	async = container_of(work, struct  async_submit_bio, work);
652 	async->submit_bio_start(async->inode, async->rw, async->bio,
653 			       async->mirror_num, async->bio_flags,
654 			       async->bio_offset);
655 }
656 
657 static void run_one_async_done(struct btrfs_work *work)
658 {
659 	struct btrfs_fs_info *fs_info;
660 	struct async_submit_bio *async;
661 	int limit;
662 
663 	async = container_of(work, struct  async_submit_bio, work);
664 	fs_info = BTRFS_I(async->inode)->root->fs_info;
665 
666 	limit = btrfs_async_submit_limit(fs_info);
667 	limit = limit * 2 / 3;
668 
669 	atomic_dec(&fs_info->nr_async_submits);
670 
671 	if (atomic_read(&fs_info->nr_async_submits) < limit &&
672 	    waitqueue_active(&fs_info->async_submit_wait))
673 		wake_up(&fs_info->async_submit_wait);
674 
675 	async->submit_bio_done(async->inode, async->rw, async->bio,
676 			       async->mirror_num, async->bio_flags,
677 			       async->bio_offset);
678 }
679 
680 static void run_one_async_free(struct btrfs_work *work)
681 {
682 	struct async_submit_bio *async;
683 
684 	async = container_of(work, struct  async_submit_bio, work);
685 	kfree(async);
686 }
687 
688 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
689 			int rw, struct bio *bio, int mirror_num,
690 			unsigned long bio_flags,
691 			u64 bio_offset,
692 			extent_submit_bio_hook_t *submit_bio_start,
693 			extent_submit_bio_hook_t *submit_bio_done)
694 {
695 	struct async_submit_bio *async;
696 
697 	async = kmalloc(sizeof(*async), GFP_NOFS);
698 	if (!async)
699 		return -ENOMEM;
700 
701 	async->inode = inode;
702 	async->rw = rw;
703 	async->bio = bio;
704 	async->mirror_num = mirror_num;
705 	async->submit_bio_start = submit_bio_start;
706 	async->submit_bio_done = submit_bio_done;
707 
708 	async->work.func = run_one_async_start;
709 	async->work.ordered_func = run_one_async_done;
710 	async->work.ordered_free = run_one_async_free;
711 
712 	async->work.flags = 0;
713 	async->bio_flags = bio_flags;
714 	async->bio_offset = bio_offset;
715 
716 	atomic_inc(&fs_info->nr_async_submits);
717 
718 	if (rw & REQ_SYNC)
719 		btrfs_set_work_high_prio(&async->work);
720 
721 	btrfs_queue_worker(&fs_info->workers, &async->work);
722 
723 	while (atomic_read(&fs_info->async_submit_draining) &&
724 	      atomic_read(&fs_info->nr_async_submits)) {
725 		wait_event(fs_info->async_submit_wait,
726 			   (atomic_read(&fs_info->nr_async_submits) == 0));
727 	}
728 
729 	return 0;
730 }
731 
732 static int btree_csum_one_bio(struct bio *bio)
733 {
734 	struct bio_vec *bvec = bio->bi_io_vec;
735 	int bio_index = 0;
736 	struct btrfs_root *root;
737 
738 	WARN_ON(bio->bi_vcnt <= 0);
739 	while (bio_index < bio->bi_vcnt) {
740 		root = BTRFS_I(bvec->bv_page->mapping->host)->root;
741 		csum_dirty_buffer(root, bvec->bv_page);
742 		bio_index++;
743 		bvec++;
744 	}
745 	return 0;
746 }
747 
748 static int __btree_submit_bio_start(struct inode *inode, int rw,
749 				    struct bio *bio, int mirror_num,
750 				    unsigned long bio_flags,
751 				    u64 bio_offset)
752 {
753 	/*
754 	 * when we're called for a write, we're already in the async
755 	 * submission context.  Just jump into btrfs_map_bio
756 	 */
757 	btree_csum_one_bio(bio);
758 	return 0;
759 }
760 
761 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
762 				 int mirror_num, unsigned long bio_flags,
763 				 u64 bio_offset)
764 {
765 	/*
766 	 * when we're called for a write, we're already in the async
767 	 * submission context.  Just jump into btrfs_map_bio
768 	 */
769 	return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
770 }
771 
772 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
773 				 int mirror_num, unsigned long bio_flags,
774 				 u64 bio_offset)
775 {
776 	int ret;
777 
778 	ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
779 					  bio, 1);
780 	BUG_ON(ret);
781 
782 	if (!(rw & REQ_WRITE)) {
783 		/*
784 		 * called for a read, do the setup so that checksum validation
785 		 * can happen in the async kernel threads
786 		 */
787 		return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
788 				     mirror_num, 0);
789 	}
790 
791 	/*
792 	 * kthread helpers are used to submit writes so that checksumming
793 	 * can happen in parallel across all CPUs
794 	 */
795 	return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
796 				   inode, rw, bio, mirror_num, 0,
797 				   bio_offset,
798 				   __btree_submit_bio_start,
799 				   __btree_submit_bio_done);
800 }
801 
802 #ifdef CONFIG_MIGRATION
803 static int btree_migratepage(struct address_space *mapping,
804 			struct page *newpage, struct page *page)
805 {
806 	/*
807 	 * we can't safely write a btree page from here,
808 	 * we haven't done the locking hook
809 	 */
810 	if (PageDirty(page))
811 		return -EAGAIN;
812 	/*
813 	 * Buffers may be managed in a filesystem specific way.
814 	 * We must have no buffers or drop them.
815 	 */
816 	if (page_has_private(page) &&
817 	    !try_to_release_page(page, GFP_KERNEL))
818 		return -EAGAIN;
819 	return migrate_page(mapping, newpage, page);
820 }
821 #endif
822 
823 static int btree_writepage(struct page *page, struct writeback_control *wbc)
824 {
825 	struct extent_io_tree *tree;
826 	struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
827 	struct extent_buffer *eb;
828 	int was_dirty;
829 
830 	tree = &BTRFS_I(page->mapping->host)->io_tree;
831 	if (!(current->flags & PF_MEMALLOC)) {
832 		return extent_write_full_page(tree, page,
833 					      btree_get_extent, wbc);
834 	}
835 
836 	redirty_page_for_writepage(wbc, page);
837 	eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
838 	WARN_ON(!eb);
839 
840 	was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
841 	if (!was_dirty) {
842 		spin_lock(&root->fs_info->delalloc_lock);
843 		root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
844 		spin_unlock(&root->fs_info->delalloc_lock);
845 	}
846 	free_extent_buffer(eb);
847 
848 	unlock_page(page);
849 	return 0;
850 }
851 
852 static int btree_writepages(struct address_space *mapping,
853 			    struct writeback_control *wbc)
854 {
855 	struct extent_io_tree *tree;
856 	tree = &BTRFS_I(mapping->host)->io_tree;
857 	if (wbc->sync_mode == WB_SYNC_NONE) {
858 		struct btrfs_root *root = BTRFS_I(mapping->host)->root;
859 		u64 num_dirty;
860 		unsigned long thresh = 32 * 1024 * 1024;
861 
862 		if (wbc->for_kupdate)
863 			return 0;
864 
865 		/* this is a bit racy, but that's ok */
866 		num_dirty = root->fs_info->dirty_metadata_bytes;
867 		if (num_dirty < thresh)
868 			return 0;
869 	}
870 	return extent_writepages(tree, mapping, btree_get_extent, wbc);
871 }
872 
873 static int btree_readpage(struct file *file, struct page *page)
874 {
875 	struct extent_io_tree *tree;
876 	tree = &BTRFS_I(page->mapping->host)->io_tree;
877 	return extent_read_full_page(tree, page, btree_get_extent);
878 }
879 
880 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
881 {
882 	struct extent_io_tree *tree;
883 	struct extent_map_tree *map;
884 	int ret;
885 
886 	if (PageWriteback(page) || PageDirty(page))
887 		return 0;
888 
889 	tree = &BTRFS_I(page->mapping->host)->io_tree;
890 	map = &BTRFS_I(page->mapping->host)->extent_tree;
891 
892 	ret = try_release_extent_state(map, tree, page, gfp_flags);
893 	if (!ret)
894 		return 0;
895 
896 	ret = try_release_extent_buffer(tree, page);
897 	if (ret == 1) {
898 		ClearPagePrivate(page);
899 		set_page_private(page, 0);
900 		page_cache_release(page);
901 	}
902 
903 	return ret;
904 }
905 
906 static void btree_invalidatepage(struct page *page, unsigned long offset)
907 {
908 	struct extent_io_tree *tree;
909 	tree = &BTRFS_I(page->mapping->host)->io_tree;
910 	extent_invalidatepage(tree, page, offset);
911 	btree_releasepage(page, GFP_NOFS);
912 	if (PagePrivate(page)) {
913 		printk(KERN_WARNING "btrfs warning page private not zero "
914 		       "on page %llu\n", (unsigned long long)page_offset(page));
915 		ClearPagePrivate(page);
916 		set_page_private(page, 0);
917 		page_cache_release(page);
918 	}
919 }
920 
921 static const struct address_space_operations btree_aops = {
922 	.readpage	= btree_readpage,
923 	.writepage	= btree_writepage,
924 	.writepages	= btree_writepages,
925 	.releasepage	= btree_releasepage,
926 	.invalidatepage = btree_invalidatepage,
927 #ifdef CONFIG_MIGRATION
928 	.migratepage	= btree_migratepage,
929 #endif
930 };
931 
932 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
933 			 u64 parent_transid)
934 {
935 	struct extent_buffer *buf = NULL;
936 	struct inode *btree_inode = root->fs_info->btree_inode;
937 	int ret = 0;
938 
939 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
940 	if (!buf)
941 		return 0;
942 	read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
943 				 buf, 0, 0, btree_get_extent, 0);
944 	free_extent_buffer(buf);
945 	return ret;
946 }
947 
948 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
949 					    u64 bytenr, u32 blocksize)
950 {
951 	struct inode *btree_inode = root->fs_info->btree_inode;
952 	struct extent_buffer *eb;
953 	eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
954 				bytenr, blocksize);
955 	return eb;
956 }
957 
958 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
959 						 u64 bytenr, u32 blocksize)
960 {
961 	struct inode *btree_inode = root->fs_info->btree_inode;
962 	struct extent_buffer *eb;
963 
964 	eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
965 				 bytenr, blocksize, NULL);
966 	return eb;
967 }
968 
969 
970 int btrfs_write_tree_block(struct extent_buffer *buf)
971 {
972 	return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
973 					buf->start + buf->len - 1);
974 }
975 
976 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
977 {
978 	return filemap_fdatawait_range(buf->first_page->mapping,
979 				       buf->start, buf->start + buf->len - 1);
980 }
981 
982 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
983 				      u32 blocksize, u64 parent_transid)
984 {
985 	struct extent_buffer *buf = NULL;
986 	int ret;
987 
988 	buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
989 	if (!buf)
990 		return NULL;
991 
992 	ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
993 
994 	if (ret == 0)
995 		set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
996 	return buf;
997 
998 }
999 
1000 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1001 		     struct extent_buffer *buf)
1002 {
1003 	struct inode *btree_inode = root->fs_info->btree_inode;
1004 	if (btrfs_header_generation(buf) ==
1005 	    root->fs_info->running_transaction->transid) {
1006 		btrfs_assert_tree_locked(buf);
1007 
1008 		if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1009 			spin_lock(&root->fs_info->delalloc_lock);
1010 			if (root->fs_info->dirty_metadata_bytes >= buf->len)
1011 				root->fs_info->dirty_metadata_bytes -= buf->len;
1012 			else
1013 				WARN_ON(1);
1014 			spin_unlock(&root->fs_info->delalloc_lock);
1015 		}
1016 
1017 		/* ugh, clear_extent_buffer_dirty needs to lock the page */
1018 		btrfs_set_lock_blocking(buf);
1019 		clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
1020 					  buf);
1021 	}
1022 	return 0;
1023 }
1024 
1025 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1026 			u32 stripesize, struct btrfs_root *root,
1027 			struct btrfs_fs_info *fs_info,
1028 			u64 objectid)
1029 {
1030 	root->node = NULL;
1031 	root->commit_root = NULL;
1032 	root->sectorsize = sectorsize;
1033 	root->nodesize = nodesize;
1034 	root->leafsize = leafsize;
1035 	root->stripesize = stripesize;
1036 	root->ref_cows = 0;
1037 	root->track_dirty = 0;
1038 	root->in_radix = 0;
1039 	root->orphan_item_inserted = 0;
1040 	root->orphan_cleanup_state = 0;
1041 
1042 	root->fs_info = fs_info;
1043 	root->objectid = objectid;
1044 	root->last_trans = 0;
1045 	root->highest_objectid = 0;
1046 	root->name = NULL;
1047 	root->in_sysfs = 0;
1048 	root->inode_tree = RB_ROOT;
1049 	INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1050 	root->block_rsv = NULL;
1051 	root->orphan_block_rsv = NULL;
1052 
1053 	INIT_LIST_HEAD(&root->dirty_list);
1054 	INIT_LIST_HEAD(&root->orphan_list);
1055 	INIT_LIST_HEAD(&root->root_list);
1056 	spin_lock_init(&root->orphan_lock);
1057 	spin_lock_init(&root->inode_lock);
1058 	spin_lock_init(&root->accounting_lock);
1059 	mutex_init(&root->objectid_mutex);
1060 	mutex_init(&root->log_mutex);
1061 	init_waitqueue_head(&root->log_writer_wait);
1062 	init_waitqueue_head(&root->log_commit_wait[0]);
1063 	init_waitqueue_head(&root->log_commit_wait[1]);
1064 	atomic_set(&root->log_commit[0], 0);
1065 	atomic_set(&root->log_commit[1], 0);
1066 	atomic_set(&root->log_writers, 0);
1067 	root->log_batch = 0;
1068 	root->log_transid = 0;
1069 	root->last_log_commit = 0;
1070 	extent_io_tree_init(&root->dirty_log_pages,
1071 			     fs_info->btree_inode->i_mapping);
1072 
1073 	memset(&root->root_key, 0, sizeof(root->root_key));
1074 	memset(&root->root_item, 0, sizeof(root->root_item));
1075 	memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1076 	memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1077 	root->defrag_trans_start = fs_info->generation;
1078 	init_completion(&root->kobj_unregister);
1079 	root->defrag_running = 0;
1080 	root->root_key.objectid = objectid;
1081 	root->anon_super.s_root = NULL;
1082 	root->anon_super.s_dev = 0;
1083 	INIT_LIST_HEAD(&root->anon_super.s_list);
1084 	INIT_LIST_HEAD(&root->anon_super.s_instances);
1085 	init_rwsem(&root->anon_super.s_umount);
1086 
1087 	return 0;
1088 }
1089 
1090 static int find_and_setup_root(struct btrfs_root *tree_root,
1091 			       struct btrfs_fs_info *fs_info,
1092 			       u64 objectid,
1093 			       struct btrfs_root *root)
1094 {
1095 	int ret;
1096 	u32 blocksize;
1097 	u64 generation;
1098 
1099 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1100 		     tree_root->sectorsize, tree_root->stripesize,
1101 		     root, fs_info, objectid);
1102 	ret = btrfs_find_last_root(tree_root, objectid,
1103 				   &root->root_item, &root->root_key);
1104 	if (ret > 0)
1105 		return -ENOENT;
1106 	BUG_ON(ret);
1107 
1108 	generation = btrfs_root_generation(&root->root_item);
1109 	blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1110 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1111 				     blocksize, generation);
1112 	if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1113 		free_extent_buffer(root->node);
1114 		return -EIO;
1115 	}
1116 	root->commit_root = btrfs_root_node(root);
1117 	return 0;
1118 }
1119 
1120 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1121 					 struct btrfs_fs_info *fs_info)
1122 {
1123 	struct btrfs_root *root;
1124 	struct btrfs_root *tree_root = fs_info->tree_root;
1125 	struct extent_buffer *leaf;
1126 
1127 	root = kzalloc(sizeof(*root), GFP_NOFS);
1128 	if (!root)
1129 		return ERR_PTR(-ENOMEM);
1130 
1131 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1132 		     tree_root->sectorsize, tree_root->stripesize,
1133 		     root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1134 
1135 	root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1136 	root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1137 	root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1138 	/*
1139 	 * log trees do not get reference counted because they go away
1140 	 * before a real commit is actually done.  They do store pointers
1141 	 * to file data extents, and those reference counts still get
1142 	 * updated (along with back refs to the log tree).
1143 	 */
1144 	root->ref_cows = 0;
1145 
1146 	leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1147 				      BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1148 	if (IS_ERR(leaf)) {
1149 		kfree(root);
1150 		return ERR_CAST(leaf);
1151 	}
1152 
1153 	memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1154 	btrfs_set_header_bytenr(leaf, leaf->start);
1155 	btrfs_set_header_generation(leaf, trans->transid);
1156 	btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1157 	btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1158 	root->node = leaf;
1159 
1160 	write_extent_buffer(root->node, root->fs_info->fsid,
1161 			    (unsigned long)btrfs_header_fsid(root->node),
1162 			    BTRFS_FSID_SIZE);
1163 	btrfs_mark_buffer_dirty(root->node);
1164 	btrfs_tree_unlock(root->node);
1165 	return root;
1166 }
1167 
1168 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1169 			     struct btrfs_fs_info *fs_info)
1170 {
1171 	struct btrfs_root *log_root;
1172 
1173 	log_root = alloc_log_tree(trans, fs_info);
1174 	if (IS_ERR(log_root))
1175 		return PTR_ERR(log_root);
1176 	WARN_ON(fs_info->log_root_tree);
1177 	fs_info->log_root_tree = log_root;
1178 	return 0;
1179 }
1180 
1181 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1182 		       struct btrfs_root *root)
1183 {
1184 	struct btrfs_root *log_root;
1185 	struct btrfs_inode_item *inode_item;
1186 
1187 	log_root = alloc_log_tree(trans, root->fs_info);
1188 	if (IS_ERR(log_root))
1189 		return PTR_ERR(log_root);
1190 
1191 	log_root->last_trans = trans->transid;
1192 	log_root->root_key.offset = root->root_key.objectid;
1193 
1194 	inode_item = &log_root->root_item.inode;
1195 	inode_item->generation = cpu_to_le64(1);
1196 	inode_item->size = cpu_to_le64(3);
1197 	inode_item->nlink = cpu_to_le32(1);
1198 	inode_item->nbytes = cpu_to_le64(root->leafsize);
1199 	inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1200 
1201 	btrfs_set_root_node(&log_root->root_item, log_root->node);
1202 
1203 	WARN_ON(root->log_root);
1204 	root->log_root = log_root;
1205 	root->log_transid = 0;
1206 	root->last_log_commit = 0;
1207 	return 0;
1208 }
1209 
1210 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1211 					       struct btrfs_key *location)
1212 {
1213 	struct btrfs_root *root;
1214 	struct btrfs_fs_info *fs_info = tree_root->fs_info;
1215 	struct btrfs_path *path;
1216 	struct extent_buffer *l;
1217 	u64 generation;
1218 	u32 blocksize;
1219 	int ret = 0;
1220 
1221 	root = kzalloc(sizeof(*root), GFP_NOFS);
1222 	if (!root)
1223 		return ERR_PTR(-ENOMEM);
1224 	if (location->offset == (u64)-1) {
1225 		ret = find_and_setup_root(tree_root, fs_info,
1226 					  location->objectid, root);
1227 		if (ret) {
1228 			kfree(root);
1229 			return ERR_PTR(ret);
1230 		}
1231 		goto out;
1232 	}
1233 
1234 	__setup_root(tree_root->nodesize, tree_root->leafsize,
1235 		     tree_root->sectorsize, tree_root->stripesize,
1236 		     root, fs_info, location->objectid);
1237 
1238 	path = btrfs_alloc_path();
1239 	if (!path) {
1240 		kfree(root);
1241 		return ERR_PTR(-ENOMEM);
1242 	}
1243 	ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1244 	if (ret == 0) {
1245 		l = path->nodes[0];
1246 		read_extent_buffer(l, &root->root_item,
1247 				btrfs_item_ptr_offset(l, path->slots[0]),
1248 				sizeof(root->root_item));
1249 		memcpy(&root->root_key, location, sizeof(*location));
1250 	}
1251 	btrfs_free_path(path);
1252 	if (ret) {
1253 		kfree(root);
1254 		if (ret > 0)
1255 			ret = -ENOENT;
1256 		return ERR_PTR(ret);
1257 	}
1258 
1259 	generation = btrfs_root_generation(&root->root_item);
1260 	blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1261 	root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1262 				     blocksize, generation);
1263 	root->commit_root = btrfs_root_node(root);
1264 	BUG_ON(!root->node);
1265 out:
1266 	if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
1267 		root->ref_cows = 1;
1268 		btrfs_check_and_init_root_item(&root->root_item);
1269 	}
1270 
1271 	return root;
1272 }
1273 
1274 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1275 					      struct btrfs_key *location)
1276 {
1277 	struct btrfs_root *root;
1278 	int ret;
1279 
1280 	if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1281 		return fs_info->tree_root;
1282 	if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1283 		return fs_info->extent_root;
1284 	if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1285 		return fs_info->chunk_root;
1286 	if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1287 		return fs_info->dev_root;
1288 	if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1289 		return fs_info->csum_root;
1290 again:
1291 	spin_lock(&fs_info->fs_roots_radix_lock);
1292 	root = radix_tree_lookup(&fs_info->fs_roots_radix,
1293 				 (unsigned long)location->objectid);
1294 	spin_unlock(&fs_info->fs_roots_radix_lock);
1295 	if (root)
1296 		return root;
1297 
1298 	root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1299 	if (IS_ERR(root))
1300 		return root;
1301 
1302 	root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1303 	if (!root->free_ino_ctl)
1304 		goto fail;
1305 	root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1306 					GFP_NOFS);
1307 	if (!root->free_ino_pinned)
1308 		goto fail;
1309 
1310 	btrfs_init_free_ino_ctl(root);
1311 	mutex_init(&root->fs_commit_mutex);
1312 	spin_lock_init(&root->cache_lock);
1313 	init_waitqueue_head(&root->cache_wait);
1314 
1315 	set_anon_super(&root->anon_super, NULL);
1316 
1317 	if (btrfs_root_refs(&root->root_item) == 0) {
1318 		ret = -ENOENT;
1319 		goto fail;
1320 	}
1321 
1322 	ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1323 	if (ret < 0)
1324 		goto fail;
1325 	if (ret == 0)
1326 		root->orphan_item_inserted = 1;
1327 
1328 	ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1329 	if (ret)
1330 		goto fail;
1331 
1332 	spin_lock(&fs_info->fs_roots_radix_lock);
1333 	ret = radix_tree_insert(&fs_info->fs_roots_radix,
1334 				(unsigned long)root->root_key.objectid,
1335 				root);
1336 	if (ret == 0)
1337 		root->in_radix = 1;
1338 
1339 	spin_unlock(&fs_info->fs_roots_radix_lock);
1340 	radix_tree_preload_end();
1341 	if (ret) {
1342 		if (ret == -EEXIST) {
1343 			free_fs_root(root);
1344 			goto again;
1345 		}
1346 		goto fail;
1347 	}
1348 
1349 	ret = btrfs_find_dead_roots(fs_info->tree_root,
1350 				    root->root_key.objectid);
1351 	WARN_ON(ret);
1352 	return root;
1353 fail:
1354 	free_fs_root(root);
1355 	return ERR_PTR(ret);
1356 }
1357 
1358 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1359 {
1360 	struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1361 	int ret = 0;
1362 	struct btrfs_device *device;
1363 	struct backing_dev_info *bdi;
1364 
1365 	rcu_read_lock();
1366 	list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1367 		if (!device->bdev)
1368 			continue;
1369 		bdi = blk_get_backing_dev_info(device->bdev);
1370 		if (bdi && bdi_congested(bdi, bdi_bits)) {
1371 			ret = 1;
1372 			break;
1373 		}
1374 	}
1375 	rcu_read_unlock();
1376 	return ret;
1377 }
1378 
1379 /*
1380  * If this fails, caller must call bdi_destroy() to get rid of the
1381  * bdi again.
1382  */
1383 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1384 {
1385 	int err;
1386 
1387 	bdi->capabilities = BDI_CAP_MAP_COPY;
1388 	err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1389 	if (err)
1390 		return err;
1391 
1392 	bdi->ra_pages	= default_backing_dev_info.ra_pages;
1393 	bdi->congested_fn	= btrfs_congested_fn;
1394 	bdi->congested_data	= info;
1395 	return 0;
1396 }
1397 
1398 static int bio_ready_for_csum(struct bio *bio)
1399 {
1400 	u64 length = 0;
1401 	u64 buf_len = 0;
1402 	u64 start = 0;
1403 	struct page *page;
1404 	struct extent_io_tree *io_tree = NULL;
1405 	struct bio_vec *bvec;
1406 	int i;
1407 	int ret;
1408 
1409 	bio_for_each_segment(bvec, bio, i) {
1410 		page = bvec->bv_page;
1411 		if (page->private == EXTENT_PAGE_PRIVATE) {
1412 			length += bvec->bv_len;
1413 			continue;
1414 		}
1415 		if (!page->private) {
1416 			length += bvec->bv_len;
1417 			continue;
1418 		}
1419 		length = bvec->bv_len;
1420 		buf_len = page->private >> 2;
1421 		start = page_offset(page) + bvec->bv_offset;
1422 		io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1423 	}
1424 	/* are we fully contained in this bio? */
1425 	if (buf_len <= length)
1426 		return 1;
1427 
1428 	ret = extent_range_uptodate(io_tree, start + length,
1429 				    start + buf_len - 1);
1430 	return ret;
1431 }
1432 
1433 /*
1434  * called by the kthread helper functions to finally call the bio end_io
1435  * functions.  This is where read checksum verification actually happens
1436  */
1437 static void end_workqueue_fn(struct btrfs_work *work)
1438 {
1439 	struct bio *bio;
1440 	struct end_io_wq *end_io_wq;
1441 	struct btrfs_fs_info *fs_info;
1442 	int error;
1443 
1444 	end_io_wq = container_of(work, struct end_io_wq, work);
1445 	bio = end_io_wq->bio;
1446 	fs_info = end_io_wq->info;
1447 
1448 	/* metadata bio reads are special because the whole tree block must
1449 	 * be checksummed at once.  This makes sure the entire block is in
1450 	 * ram and up to date before trying to verify things.  For
1451 	 * blocksize <= pagesize, it is basically a noop
1452 	 */
1453 	if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1454 	    !bio_ready_for_csum(bio)) {
1455 		btrfs_queue_worker(&fs_info->endio_meta_workers,
1456 				   &end_io_wq->work);
1457 		return;
1458 	}
1459 	error = end_io_wq->error;
1460 	bio->bi_private = end_io_wq->private;
1461 	bio->bi_end_io = end_io_wq->end_io;
1462 	kfree(end_io_wq);
1463 	bio_endio(bio, error);
1464 }
1465 
1466 static int cleaner_kthread(void *arg)
1467 {
1468 	struct btrfs_root *root = arg;
1469 
1470 	do {
1471 		vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1472 
1473 		if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1474 		    mutex_trylock(&root->fs_info->cleaner_mutex)) {
1475 			btrfs_run_delayed_iputs(root);
1476 			btrfs_clean_old_snapshots(root);
1477 			mutex_unlock(&root->fs_info->cleaner_mutex);
1478 			btrfs_run_defrag_inodes(root->fs_info);
1479 		}
1480 
1481 		if (freezing(current)) {
1482 			refrigerator();
1483 		} else {
1484 			set_current_state(TASK_INTERRUPTIBLE);
1485 			if (!kthread_should_stop())
1486 				schedule();
1487 			__set_current_state(TASK_RUNNING);
1488 		}
1489 	} while (!kthread_should_stop());
1490 	return 0;
1491 }
1492 
1493 static int transaction_kthread(void *arg)
1494 {
1495 	struct btrfs_root *root = arg;
1496 	struct btrfs_trans_handle *trans;
1497 	struct btrfs_transaction *cur;
1498 	u64 transid;
1499 	unsigned long now;
1500 	unsigned long delay;
1501 	int ret;
1502 
1503 	do {
1504 		delay = HZ * 30;
1505 		vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1506 		mutex_lock(&root->fs_info->transaction_kthread_mutex);
1507 
1508 		spin_lock(&root->fs_info->trans_lock);
1509 		cur = root->fs_info->running_transaction;
1510 		if (!cur) {
1511 			spin_unlock(&root->fs_info->trans_lock);
1512 			goto sleep;
1513 		}
1514 
1515 		now = get_seconds();
1516 		if (!cur->blocked &&
1517 		    (now < cur->start_time || now - cur->start_time < 30)) {
1518 			spin_unlock(&root->fs_info->trans_lock);
1519 			delay = HZ * 5;
1520 			goto sleep;
1521 		}
1522 		transid = cur->transid;
1523 		spin_unlock(&root->fs_info->trans_lock);
1524 
1525 		trans = btrfs_join_transaction(root);
1526 		BUG_ON(IS_ERR(trans));
1527 		if (transid == trans->transid) {
1528 			ret = btrfs_commit_transaction(trans, root);
1529 			BUG_ON(ret);
1530 		} else {
1531 			btrfs_end_transaction(trans, root);
1532 		}
1533 sleep:
1534 		wake_up_process(root->fs_info->cleaner_kthread);
1535 		mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1536 
1537 		if (freezing(current)) {
1538 			refrigerator();
1539 		} else {
1540 			set_current_state(TASK_INTERRUPTIBLE);
1541 			if (!kthread_should_stop() &&
1542 			    !btrfs_transaction_blocked(root->fs_info))
1543 				schedule_timeout(delay);
1544 			__set_current_state(TASK_RUNNING);
1545 		}
1546 	} while (!kthread_should_stop());
1547 	return 0;
1548 }
1549 
1550 struct btrfs_root *open_ctree(struct super_block *sb,
1551 			      struct btrfs_fs_devices *fs_devices,
1552 			      char *options)
1553 {
1554 	u32 sectorsize;
1555 	u32 nodesize;
1556 	u32 leafsize;
1557 	u32 blocksize;
1558 	u32 stripesize;
1559 	u64 generation;
1560 	u64 features;
1561 	struct btrfs_key location;
1562 	struct buffer_head *bh;
1563 	struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1564 						 GFP_NOFS);
1565 	struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1566 						 GFP_NOFS);
1567 	struct btrfs_root *tree_root = btrfs_sb(sb);
1568 	struct btrfs_fs_info *fs_info = NULL;
1569 	struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1570 						GFP_NOFS);
1571 	struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1572 					      GFP_NOFS);
1573 	struct btrfs_root *log_tree_root;
1574 
1575 	int ret;
1576 	int err = -EINVAL;
1577 
1578 	struct btrfs_super_block *disk_super;
1579 
1580 	if (!extent_root || !tree_root || !tree_root->fs_info ||
1581 	    !chunk_root || !dev_root || !csum_root) {
1582 		err = -ENOMEM;
1583 		goto fail;
1584 	}
1585 	fs_info = tree_root->fs_info;
1586 
1587 	ret = init_srcu_struct(&fs_info->subvol_srcu);
1588 	if (ret) {
1589 		err = ret;
1590 		goto fail;
1591 	}
1592 
1593 	ret = setup_bdi(fs_info, &fs_info->bdi);
1594 	if (ret) {
1595 		err = ret;
1596 		goto fail_srcu;
1597 	}
1598 
1599 	fs_info->btree_inode = new_inode(sb);
1600 	if (!fs_info->btree_inode) {
1601 		err = -ENOMEM;
1602 		goto fail_bdi;
1603 	}
1604 
1605 	fs_info->btree_inode->i_mapping->flags &= ~__GFP_FS;
1606 
1607 	INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1608 	INIT_LIST_HEAD(&fs_info->trans_list);
1609 	INIT_LIST_HEAD(&fs_info->dead_roots);
1610 	INIT_LIST_HEAD(&fs_info->delayed_iputs);
1611 	INIT_LIST_HEAD(&fs_info->hashers);
1612 	INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1613 	INIT_LIST_HEAD(&fs_info->ordered_operations);
1614 	INIT_LIST_HEAD(&fs_info->caching_block_groups);
1615 	spin_lock_init(&fs_info->delalloc_lock);
1616 	spin_lock_init(&fs_info->trans_lock);
1617 	spin_lock_init(&fs_info->ref_cache_lock);
1618 	spin_lock_init(&fs_info->fs_roots_radix_lock);
1619 	spin_lock_init(&fs_info->delayed_iput_lock);
1620 	spin_lock_init(&fs_info->defrag_inodes_lock);
1621 
1622 	init_completion(&fs_info->kobj_unregister);
1623 	fs_info->tree_root = tree_root;
1624 	fs_info->extent_root = extent_root;
1625 	fs_info->csum_root = csum_root;
1626 	fs_info->chunk_root = chunk_root;
1627 	fs_info->dev_root = dev_root;
1628 	fs_info->fs_devices = fs_devices;
1629 	INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1630 	INIT_LIST_HEAD(&fs_info->space_info);
1631 	btrfs_mapping_init(&fs_info->mapping_tree);
1632 	btrfs_init_block_rsv(&fs_info->global_block_rsv);
1633 	btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1634 	btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1635 	btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1636 	btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1637 	INIT_LIST_HEAD(&fs_info->durable_block_rsv_list);
1638 	mutex_init(&fs_info->durable_block_rsv_mutex);
1639 	atomic_set(&fs_info->nr_async_submits, 0);
1640 	atomic_set(&fs_info->async_delalloc_pages, 0);
1641 	atomic_set(&fs_info->async_submit_draining, 0);
1642 	atomic_set(&fs_info->nr_async_bios, 0);
1643 	atomic_set(&fs_info->defrag_running, 0);
1644 	fs_info->sb = sb;
1645 	fs_info->max_inline = 8192 * 1024;
1646 	fs_info->metadata_ratio = 0;
1647 	fs_info->defrag_inodes = RB_ROOT;
1648 	fs_info->trans_no_join = 0;
1649 
1650 	fs_info->thread_pool_size = min_t(unsigned long,
1651 					  num_online_cpus() + 2, 8);
1652 
1653 	INIT_LIST_HEAD(&fs_info->ordered_extents);
1654 	spin_lock_init(&fs_info->ordered_extent_lock);
1655 	fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
1656 					GFP_NOFS);
1657 	if (!fs_info->delayed_root) {
1658 		err = -ENOMEM;
1659 		goto fail_iput;
1660 	}
1661 	btrfs_init_delayed_root(fs_info->delayed_root);
1662 
1663 	mutex_init(&fs_info->scrub_lock);
1664 	atomic_set(&fs_info->scrubs_running, 0);
1665 	atomic_set(&fs_info->scrub_pause_req, 0);
1666 	atomic_set(&fs_info->scrubs_paused, 0);
1667 	atomic_set(&fs_info->scrub_cancel_req, 0);
1668 	init_waitqueue_head(&fs_info->scrub_pause_wait);
1669 	init_rwsem(&fs_info->scrub_super_lock);
1670 	fs_info->scrub_workers_refcnt = 0;
1671 	btrfs_init_workers(&fs_info->scrub_workers, "scrub",
1672 			   fs_info->thread_pool_size, &fs_info->generic_worker);
1673 
1674 	sb->s_blocksize = 4096;
1675 	sb->s_blocksize_bits = blksize_bits(4096);
1676 	sb->s_bdi = &fs_info->bdi;
1677 
1678 	fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1679 	fs_info->btree_inode->i_nlink = 1;
1680 	/*
1681 	 * we set the i_size on the btree inode to the max possible int.
1682 	 * the real end of the address space is determined by all of
1683 	 * the devices in the system
1684 	 */
1685 	fs_info->btree_inode->i_size = OFFSET_MAX;
1686 	fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1687 	fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1688 
1689 	RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1690 	extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1691 			     fs_info->btree_inode->i_mapping);
1692 	extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
1693 
1694 	BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1695 
1696 	BTRFS_I(fs_info->btree_inode)->root = tree_root;
1697 	memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1698 	       sizeof(struct btrfs_key));
1699 	BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1700 	insert_inode_hash(fs_info->btree_inode);
1701 
1702 	spin_lock_init(&fs_info->block_group_cache_lock);
1703 	fs_info->block_group_cache_tree = RB_ROOT;
1704 
1705 	extent_io_tree_init(&fs_info->freed_extents[0],
1706 			     fs_info->btree_inode->i_mapping);
1707 	extent_io_tree_init(&fs_info->freed_extents[1],
1708 			     fs_info->btree_inode->i_mapping);
1709 	fs_info->pinned_extents = &fs_info->freed_extents[0];
1710 	fs_info->do_barriers = 1;
1711 
1712 
1713 	mutex_init(&fs_info->ordered_operations_mutex);
1714 	mutex_init(&fs_info->tree_log_mutex);
1715 	mutex_init(&fs_info->chunk_mutex);
1716 	mutex_init(&fs_info->transaction_kthread_mutex);
1717 	mutex_init(&fs_info->cleaner_mutex);
1718 	mutex_init(&fs_info->volume_mutex);
1719 	init_rwsem(&fs_info->extent_commit_sem);
1720 	init_rwsem(&fs_info->cleanup_work_sem);
1721 	init_rwsem(&fs_info->subvol_sem);
1722 
1723 	btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1724 	btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1725 
1726 	init_waitqueue_head(&fs_info->transaction_throttle);
1727 	init_waitqueue_head(&fs_info->transaction_wait);
1728 	init_waitqueue_head(&fs_info->transaction_blocked_wait);
1729 	init_waitqueue_head(&fs_info->async_submit_wait);
1730 
1731 	__setup_root(4096, 4096, 4096, 4096, tree_root,
1732 		     fs_info, BTRFS_ROOT_TREE_OBJECTID);
1733 
1734 	bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1735 	if (!bh) {
1736 		err = -EINVAL;
1737 		goto fail_alloc;
1738 	}
1739 
1740 	memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1741 	memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1742 	       sizeof(fs_info->super_for_commit));
1743 	brelse(bh);
1744 
1745 	memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1746 
1747 	disk_super = &fs_info->super_copy;
1748 	if (!btrfs_super_root(disk_super))
1749 		goto fail_alloc;
1750 
1751 	/* check FS state, whether FS is broken. */
1752 	fs_info->fs_state |= btrfs_super_flags(disk_super);
1753 
1754 	btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
1755 
1756 	/*
1757 	 * In the long term, we'll store the compression type in the super
1758 	 * block, and it'll be used for per file compression control.
1759 	 */
1760 	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
1761 
1762 	ret = btrfs_parse_options(tree_root, options);
1763 	if (ret) {
1764 		err = ret;
1765 		goto fail_alloc;
1766 	}
1767 
1768 	features = btrfs_super_incompat_flags(disk_super) &
1769 		~BTRFS_FEATURE_INCOMPAT_SUPP;
1770 	if (features) {
1771 		printk(KERN_ERR "BTRFS: couldn't mount because of "
1772 		       "unsupported optional features (%Lx).\n",
1773 		       (unsigned long long)features);
1774 		err = -EINVAL;
1775 		goto fail_alloc;
1776 	}
1777 
1778 	features = btrfs_super_incompat_flags(disk_super);
1779 	features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1780 	if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
1781 		features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
1782 	btrfs_set_super_incompat_flags(disk_super, features);
1783 
1784 	features = btrfs_super_compat_ro_flags(disk_super) &
1785 		~BTRFS_FEATURE_COMPAT_RO_SUPP;
1786 	if (!(sb->s_flags & MS_RDONLY) && features) {
1787 		printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1788 		       "unsupported option features (%Lx).\n",
1789 		       (unsigned long long)features);
1790 		err = -EINVAL;
1791 		goto fail_alloc;
1792 	}
1793 
1794 	btrfs_init_workers(&fs_info->generic_worker,
1795 			   "genwork", 1, NULL);
1796 
1797 	btrfs_init_workers(&fs_info->workers, "worker",
1798 			   fs_info->thread_pool_size,
1799 			   &fs_info->generic_worker);
1800 
1801 	btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1802 			   fs_info->thread_pool_size,
1803 			   &fs_info->generic_worker);
1804 
1805 	btrfs_init_workers(&fs_info->submit_workers, "submit",
1806 			   min_t(u64, fs_devices->num_devices,
1807 			   fs_info->thread_pool_size),
1808 			   &fs_info->generic_worker);
1809 
1810 	/* a higher idle thresh on the submit workers makes it much more
1811 	 * likely that bios will be send down in a sane order to the
1812 	 * devices
1813 	 */
1814 	fs_info->submit_workers.idle_thresh = 64;
1815 
1816 	fs_info->workers.idle_thresh = 16;
1817 	fs_info->workers.ordered = 1;
1818 
1819 	fs_info->delalloc_workers.idle_thresh = 2;
1820 	fs_info->delalloc_workers.ordered = 1;
1821 
1822 	btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1823 			   &fs_info->generic_worker);
1824 	btrfs_init_workers(&fs_info->endio_workers, "endio",
1825 			   fs_info->thread_pool_size,
1826 			   &fs_info->generic_worker);
1827 	btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1828 			   fs_info->thread_pool_size,
1829 			   &fs_info->generic_worker);
1830 	btrfs_init_workers(&fs_info->endio_meta_write_workers,
1831 			   "endio-meta-write", fs_info->thread_pool_size,
1832 			   &fs_info->generic_worker);
1833 	btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1834 			   fs_info->thread_pool_size,
1835 			   &fs_info->generic_worker);
1836 	btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
1837 			   1, &fs_info->generic_worker);
1838 	btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
1839 			   fs_info->thread_pool_size,
1840 			   &fs_info->generic_worker);
1841 
1842 	/*
1843 	 * endios are largely parallel and should have a very
1844 	 * low idle thresh
1845 	 */
1846 	fs_info->endio_workers.idle_thresh = 4;
1847 	fs_info->endio_meta_workers.idle_thresh = 4;
1848 
1849 	fs_info->endio_write_workers.idle_thresh = 2;
1850 	fs_info->endio_meta_write_workers.idle_thresh = 2;
1851 
1852 	btrfs_start_workers(&fs_info->workers, 1);
1853 	btrfs_start_workers(&fs_info->generic_worker, 1);
1854 	btrfs_start_workers(&fs_info->submit_workers, 1);
1855 	btrfs_start_workers(&fs_info->delalloc_workers, 1);
1856 	btrfs_start_workers(&fs_info->fixup_workers, 1);
1857 	btrfs_start_workers(&fs_info->endio_workers, 1);
1858 	btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1859 	btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1860 	btrfs_start_workers(&fs_info->endio_write_workers, 1);
1861 	btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
1862 	btrfs_start_workers(&fs_info->delayed_workers, 1);
1863 
1864 	fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1865 	fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1866 				    4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1867 
1868 	nodesize = btrfs_super_nodesize(disk_super);
1869 	leafsize = btrfs_super_leafsize(disk_super);
1870 	sectorsize = btrfs_super_sectorsize(disk_super);
1871 	stripesize = btrfs_super_stripesize(disk_super);
1872 	tree_root->nodesize = nodesize;
1873 	tree_root->leafsize = leafsize;
1874 	tree_root->sectorsize = sectorsize;
1875 	tree_root->stripesize = stripesize;
1876 
1877 	sb->s_blocksize = sectorsize;
1878 	sb->s_blocksize_bits = blksize_bits(sectorsize);
1879 
1880 	if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1881 		    sizeof(disk_super->magic))) {
1882 		printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1883 		goto fail_sb_buffer;
1884 	}
1885 
1886 	mutex_lock(&fs_info->chunk_mutex);
1887 	ret = btrfs_read_sys_array(tree_root);
1888 	mutex_unlock(&fs_info->chunk_mutex);
1889 	if (ret) {
1890 		printk(KERN_WARNING "btrfs: failed to read the system "
1891 		       "array on %s\n", sb->s_id);
1892 		goto fail_sb_buffer;
1893 	}
1894 
1895 	blocksize = btrfs_level_size(tree_root,
1896 				     btrfs_super_chunk_root_level(disk_super));
1897 	generation = btrfs_super_chunk_root_generation(disk_super);
1898 
1899 	__setup_root(nodesize, leafsize, sectorsize, stripesize,
1900 		     chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1901 
1902 	chunk_root->node = read_tree_block(chunk_root,
1903 					   btrfs_super_chunk_root(disk_super),
1904 					   blocksize, generation);
1905 	BUG_ON(!chunk_root->node);
1906 	if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
1907 		printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
1908 		       sb->s_id);
1909 		goto fail_chunk_root;
1910 	}
1911 	btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
1912 	chunk_root->commit_root = btrfs_root_node(chunk_root);
1913 
1914 	read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1915 	   (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1916 	   BTRFS_UUID_SIZE);
1917 
1918 	mutex_lock(&fs_info->chunk_mutex);
1919 	ret = btrfs_read_chunk_tree(chunk_root);
1920 	mutex_unlock(&fs_info->chunk_mutex);
1921 	if (ret) {
1922 		printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
1923 		       sb->s_id);
1924 		goto fail_chunk_root;
1925 	}
1926 
1927 	btrfs_close_extra_devices(fs_devices);
1928 
1929 	blocksize = btrfs_level_size(tree_root,
1930 				     btrfs_super_root_level(disk_super));
1931 	generation = btrfs_super_generation(disk_super);
1932 
1933 	tree_root->node = read_tree_block(tree_root,
1934 					  btrfs_super_root(disk_super),
1935 					  blocksize, generation);
1936 	if (!tree_root->node)
1937 		goto fail_chunk_root;
1938 	if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
1939 		printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
1940 		       sb->s_id);
1941 		goto fail_tree_root;
1942 	}
1943 	btrfs_set_root_node(&tree_root->root_item, tree_root->node);
1944 	tree_root->commit_root = btrfs_root_node(tree_root);
1945 
1946 	ret = find_and_setup_root(tree_root, fs_info,
1947 				  BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1948 	if (ret)
1949 		goto fail_tree_root;
1950 	extent_root->track_dirty = 1;
1951 
1952 	ret = find_and_setup_root(tree_root, fs_info,
1953 				  BTRFS_DEV_TREE_OBJECTID, dev_root);
1954 	if (ret)
1955 		goto fail_extent_root;
1956 	dev_root->track_dirty = 1;
1957 
1958 	ret = find_and_setup_root(tree_root, fs_info,
1959 				  BTRFS_CSUM_TREE_OBJECTID, csum_root);
1960 	if (ret)
1961 		goto fail_dev_root;
1962 
1963 	csum_root->track_dirty = 1;
1964 
1965 	fs_info->generation = generation;
1966 	fs_info->last_trans_committed = generation;
1967 	fs_info->data_alloc_profile = (u64)-1;
1968 	fs_info->metadata_alloc_profile = (u64)-1;
1969 	fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1970 
1971 	ret = btrfs_init_space_info(fs_info);
1972 	if (ret) {
1973 		printk(KERN_ERR "Failed to initial space info: %d\n", ret);
1974 		goto fail_block_groups;
1975 	}
1976 
1977 	ret = btrfs_read_block_groups(extent_root);
1978 	if (ret) {
1979 		printk(KERN_ERR "Failed to read block groups: %d\n", ret);
1980 		goto fail_block_groups;
1981 	}
1982 
1983 	fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1984 					       "btrfs-cleaner");
1985 	if (IS_ERR(fs_info->cleaner_kthread))
1986 		goto fail_block_groups;
1987 
1988 	fs_info->transaction_kthread = kthread_run(transaction_kthread,
1989 						   tree_root,
1990 						   "btrfs-transaction");
1991 	if (IS_ERR(fs_info->transaction_kthread))
1992 		goto fail_cleaner;
1993 
1994 	if (!btrfs_test_opt(tree_root, SSD) &&
1995 	    !btrfs_test_opt(tree_root, NOSSD) &&
1996 	    !fs_info->fs_devices->rotating) {
1997 		printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
1998 		       "mode\n");
1999 		btrfs_set_opt(fs_info->mount_opt, SSD);
2000 	}
2001 
2002 	/* do not make disk changes in broken FS */
2003 	if (btrfs_super_log_root(disk_super) != 0 &&
2004 	    !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
2005 		u64 bytenr = btrfs_super_log_root(disk_super);
2006 
2007 		if (fs_devices->rw_devices == 0) {
2008 			printk(KERN_WARNING "Btrfs log replay required "
2009 			       "on RO media\n");
2010 			err = -EIO;
2011 			goto fail_trans_kthread;
2012 		}
2013 		blocksize =
2014 		     btrfs_level_size(tree_root,
2015 				      btrfs_super_log_root_level(disk_super));
2016 
2017 		log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
2018 		if (!log_tree_root) {
2019 			err = -ENOMEM;
2020 			goto fail_trans_kthread;
2021 		}
2022 
2023 		__setup_root(nodesize, leafsize, sectorsize, stripesize,
2024 			     log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2025 
2026 		log_tree_root->node = read_tree_block(tree_root, bytenr,
2027 						      blocksize,
2028 						      generation + 1);
2029 		ret = btrfs_recover_log_trees(log_tree_root);
2030 		BUG_ON(ret);
2031 
2032 		if (sb->s_flags & MS_RDONLY) {
2033 			ret =  btrfs_commit_super(tree_root);
2034 			BUG_ON(ret);
2035 		}
2036 	}
2037 
2038 	ret = btrfs_find_orphan_roots(tree_root);
2039 	BUG_ON(ret);
2040 
2041 	if (!(sb->s_flags & MS_RDONLY)) {
2042 		ret = btrfs_cleanup_fs_roots(fs_info);
2043 		BUG_ON(ret);
2044 
2045 		ret = btrfs_recover_relocation(tree_root);
2046 		if (ret < 0) {
2047 			printk(KERN_WARNING
2048 			       "btrfs: failed to recover relocation\n");
2049 			err = -EINVAL;
2050 			goto fail_trans_kthread;
2051 		}
2052 	}
2053 
2054 	location.objectid = BTRFS_FS_TREE_OBJECTID;
2055 	location.type = BTRFS_ROOT_ITEM_KEY;
2056 	location.offset = (u64)-1;
2057 
2058 	fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2059 	if (!fs_info->fs_root)
2060 		goto fail_trans_kthread;
2061 	if (IS_ERR(fs_info->fs_root)) {
2062 		err = PTR_ERR(fs_info->fs_root);
2063 		goto fail_trans_kthread;
2064 	}
2065 
2066 	if (!(sb->s_flags & MS_RDONLY)) {
2067 		down_read(&fs_info->cleanup_work_sem);
2068 		err = btrfs_orphan_cleanup(fs_info->fs_root);
2069 		if (!err)
2070 			err = btrfs_orphan_cleanup(fs_info->tree_root);
2071 		up_read(&fs_info->cleanup_work_sem);
2072 		if (err) {
2073 			close_ctree(tree_root);
2074 			return ERR_PTR(err);
2075 		}
2076 	}
2077 
2078 	return tree_root;
2079 
2080 fail_trans_kthread:
2081 	kthread_stop(fs_info->transaction_kthread);
2082 fail_cleaner:
2083 	kthread_stop(fs_info->cleaner_kthread);
2084 
2085 	/*
2086 	 * make sure we're done with the btree inode before we stop our
2087 	 * kthreads
2088 	 */
2089 	filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2090 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2091 
2092 fail_block_groups:
2093 	btrfs_free_block_groups(fs_info);
2094 	free_extent_buffer(csum_root->node);
2095 	free_extent_buffer(csum_root->commit_root);
2096 fail_dev_root:
2097 	free_extent_buffer(dev_root->node);
2098 	free_extent_buffer(dev_root->commit_root);
2099 fail_extent_root:
2100 	free_extent_buffer(extent_root->node);
2101 	free_extent_buffer(extent_root->commit_root);
2102 fail_tree_root:
2103 	free_extent_buffer(tree_root->node);
2104 	free_extent_buffer(tree_root->commit_root);
2105 fail_chunk_root:
2106 	free_extent_buffer(chunk_root->node);
2107 	free_extent_buffer(chunk_root->commit_root);
2108 fail_sb_buffer:
2109 	btrfs_stop_workers(&fs_info->generic_worker);
2110 	btrfs_stop_workers(&fs_info->fixup_workers);
2111 	btrfs_stop_workers(&fs_info->delalloc_workers);
2112 	btrfs_stop_workers(&fs_info->workers);
2113 	btrfs_stop_workers(&fs_info->endio_workers);
2114 	btrfs_stop_workers(&fs_info->endio_meta_workers);
2115 	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2116 	btrfs_stop_workers(&fs_info->endio_write_workers);
2117 	btrfs_stop_workers(&fs_info->endio_freespace_worker);
2118 	btrfs_stop_workers(&fs_info->submit_workers);
2119 	btrfs_stop_workers(&fs_info->delayed_workers);
2120 fail_alloc:
2121 	kfree(fs_info->delayed_root);
2122 fail_iput:
2123 	invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2124 	iput(fs_info->btree_inode);
2125 
2126 	btrfs_close_devices(fs_info->fs_devices);
2127 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
2128 fail_bdi:
2129 	bdi_destroy(&fs_info->bdi);
2130 fail_srcu:
2131 	cleanup_srcu_struct(&fs_info->subvol_srcu);
2132 fail:
2133 	kfree(extent_root);
2134 	kfree(tree_root);
2135 	kfree(fs_info);
2136 	kfree(chunk_root);
2137 	kfree(dev_root);
2138 	kfree(csum_root);
2139 	return ERR_PTR(err);
2140 }
2141 
2142 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2143 {
2144 	char b[BDEVNAME_SIZE];
2145 
2146 	if (uptodate) {
2147 		set_buffer_uptodate(bh);
2148 	} else {
2149 		printk_ratelimited(KERN_WARNING "lost page write due to "
2150 					"I/O error on %s\n",
2151 				       bdevname(bh->b_bdev, b));
2152 		/* note, we dont' set_buffer_write_io_error because we have
2153 		 * our own ways of dealing with the IO errors
2154 		 */
2155 		clear_buffer_uptodate(bh);
2156 	}
2157 	unlock_buffer(bh);
2158 	put_bh(bh);
2159 }
2160 
2161 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2162 {
2163 	struct buffer_head *bh;
2164 	struct buffer_head *latest = NULL;
2165 	struct btrfs_super_block *super;
2166 	int i;
2167 	u64 transid = 0;
2168 	u64 bytenr;
2169 
2170 	/* we would like to check all the supers, but that would make
2171 	 * a btrfs mount succeed after a mkfs from a different FS.
2172 	 * So, we need to add a special mount option to scan for
2173 	 * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2174 	 */
2175 	for (i = 0; i < 1; i++) {
2176 		bytenr = btrfs_sb_offset(i);
2177 		if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2178 			break;
2179 		bh = __bread(bdev, bytenr / 4096, 4096);
2180 		if (!bh)
2181 			continue;
2182 
2183 		super = (struct btrfs_super_block *)bh->b_data;
2184 		if (btrfs_super_bytenr(super) != bytenr ||
2185 		    strncmp((char *)(&super->magic), BTRFS_MAGIC,
2186 			    sizeof(super->magic))) {
2187 			brelse(bh);
2188 			continue;
2189 		}
2190 
2191 		if (!latest || btrfs_super_generation(super) > transid) {
2192 			brelse(latest);
2193 			latest = bh;
2194 			transid = btrfs_super_generation(super);
2195 		} else {
2196 			brelse(bh);
2197 		}
2198 	}
2199 	return latest;
2200 }
2201 
2202 /*
2203  * this should be called twice, once with wait == 0 and
2204  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2205  * we write are pinned.
2206  *
2207  * They are released when wait == 1 is done.
2208  * max_mirrors must be the same for both runs, and it indicates how
2209  * many supers on this one device should be written.
2210  *
2211  * max_mirrors == 0 means to write them all.
2212  */
2213 static int write_dev_supers(struct btrfs_device *device,
2214 			    struct btrfs_super_block *sb,
2215 			    int do_barriers, int wait, int max_mirrors)
2216 {
2217 	struct buffer_head *bh;
2218 	int i;
2219 	int ret;
2220 	int errors = 0;
2221 	u32 crc;
2222 	u64 bytenr;
2223 	int last_barrier = 0;
2224 
2225 	if (max_mirrors == 0)
2226 		max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2227 
2228 	/* make sure only the last submit_bh does a barrier */
2229 	if (do_barriers) {
2230 		for (i = 0; i < max_mirrors; i++) {
2231 			bytenr = btrfs_sb_offset(i);
2232 			if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2233 			    device->total_bytes)
2234 				break;
2235 			last_barrier = i;
2236 		}
2237 	}
2238 
2239 	for (i = 0; i < max_mirrors; i++) {
2240 		bytenr = btrfs_sb_offset(i);
2241 		if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2242 			break;
2243 
2244 		if (wait) {
2245 			bh = __find_get_block(device->bdev, bytenr / 4096,
2246 					      BTRFS_SUPER_INFO_SIZE);
2247 			BUG_ON(!bh);
2248 			wait_on_buffer(bh);
2249 			if (!buffer_uptodate(bh))
2250 				errors++;
2251 
2252 			/* drop our reference */
2253 			brelse(bh);
2254 
2255 			/* drop the reference from the wait == 0 run */
2256 			brelse(bh);
2257 			continue;
2258 		} else {
2259 			btrfs_set_super_bytenr(sb, bytenr);
2260 
2261 			crc = ~(u32)0;
2262 			crc = btrfs_csum_data(NULL, (char *)sb +
2263 					      BTRFS_CSUM_SIZE, crc,
2264 					      BTRFS_SUPER_INFO_SIZE -
2265 					      BTRFS_CSUM_SIZE);
2266 			btrfs_csum_final(crc, sb->csum);
2267 
2268 			/*
2269 			 * one reference for us, and we leave it for the
2270 			 * caller
2271 			 */
2272 			bh = __getblk(device->bdev, bytenr / 4096,
2273 				      BTRFS_SUPER_INFO_SIZE);
2274 			memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2275 
2276 			/* one reference for submit_bh */
2277 			get_bh(bh);
2278 
2279 			set_buffer_uptodate(bh);
2280 			lock_buffer(bh);
2281 			bh->b_end_io = btrfs_end_buffer_write_sync;
2282 		}
2283 
2284 		if (i == last_barrier && do_barriers)
2285 			ret = submit_bh(WRITE_FLUSH_FUA, bh);
2286 		else
2287 			ret = submit_bh(WRITE_SYNC, bh);
2288 
2289 		if (ret)
2290 			errors++;
2291 	}
2292 	return errors < i ? 0 : -1;
2293 }
2294 
2295 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2296 {
2297 	struct list_head *head;
2298 	struct btrfs_device *dev;
2299 	struct btrfs_super_block *sb;
2300 	struct btrfs_dev_item *dev_item;
2301 	int ret;
2302 	int do_barriers;
2303 	int max_errors;
2304 	int total_errors = 0;
2305 	u64 flags;
2306 
2307 	max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2308 	do_barriers = !btrfs_test_opt(root, NOBARRIER);
2309 
2310 	sb = &root->fs_info->super_for_commit;
2311 	dev_item = &sb->dev_item;
2312 
2313 	mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2314 	head = &root->fs_info->fs_devices->devices;
2315 	list_for_each_entry_rcu(dev, head, dev_list) {
2316 		if (!dev->bdev) {
2317 			total_errors++;
2318 			continue;
2319 		}
2320 		if (!dev->in_fs_metadata || !dev->writeable)
2321 			continue;
2322 
2323 		btrfs_set_stack_device_generation(dev_item, 0);
2324 		btrfs_set_stack_device_type(dev_item, dev->type);
2325 		btrfs_set_stack_device_id(dev_item, dev->devid);
2326 		btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2327 		btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2328 		btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2329 		btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2330 		btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2331 		memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2332 		memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2333 
2334 		flags = btrfs_super_flags(sb);
2335 		btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2336 
2337 		ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2338 		if (ret)
2339 			total_errors++;
2340 	}
2341 	if (total_errors > max_errors) {
2342 		printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2343 		       total_errors);
2344 		BUG();
2345 	}
2346 
2347 	total_errors = 0;
2348 	list_for_each_entry_rcu(dev, head, dev_list) {
2349 		if (!dev->bdev)
2350 			continue;
2351 		if (!dev->in_fs_metadata || !dev->writeable)
2352 			continue;
2353 
2354 		ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2355 		if (ret)
2356 			total_errors++;
2357 	}
2358 	mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2359 	if (total_errors > max_errors) {
2360 		printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2361 		       total_errors);
2362 		BUG();
2363 	}
2364 	return 0;
2365 }
2366 
2367 int write_ctree_super(struct btrfs_trans_handle *trans,
2368 		      struct btrfs_root *root, int max_mirrors)
2369 {
2370 	int ret;
2371 
2372 	ret = write_all_supers(root, max_mirrors);
2373 	return ret;
2374 }
2375 
2376 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2377 {
2378 	spin_lock(&fs_info->fs_roots_radix_lock);
2379 	radix_tree_delete(&fs_info->fs_roots_radix,
2380 			  (unsigned long)root->root_key.objectid);
2381 	spin_unlock(&fs_info->fs_roots_radix_lock);
2382 
2383 	if (btrfs_root_refs(&root->root_item) == 0)
2384 		synchronize_srcu(&fs_info->subvol_srcu);
2385 
2386 	__btrfs_remove_free_space_cache(root->free_ino_pinned);
2387 	__btrfs_remove_free_space_cache(root->free_ino_ctl);
2388 	free_fs_root(root);
2389 	return 0;
2390 }
2391 
2392 static void free_fs_root(struct btrfs_root *root)
2393 {
2394 	iput(root->cache_inode);
2395 	WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2396 	if (root->anon_super.s_dev) {
2397 		down_write(&root->anon_super.s_umount);
2398 		kill_anon_super(&root->anon_super);
2399 	}
2400 	free_extent_buffer(root->node);
2401 	free_extent_buffer(root->commit_root);
2402 	kfree(root->free_ino_ctl);
2403 	kfree(root->free_ino_pinned);
2404 	kfree(root->name);
2405 	kfree(root);
2406 }
2407 
2408 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2409 {
2410 	int ret;
2411 	struct btrfs_root *gang[8];
2412 	int i;
2413 
2414 	while (!list_empty(&fs_info->dead_roots)) {
2415 		gang[0] = list_entry(fs_info->dead_roots.next,
2416 				     struct btrfs_root, root_list);
2417 		list_del(&gang[0]->root_list);
2418 
2419 		if (gang[0]->in_radix) {
2420 			btrfs_free_fs_root(fs_info, gang[0]);
2421 		} else {
2422 			free_extent_buffer(gang[0]->node);
2423 			free_extent_buffer(gang[0]->commit_root);
2424 			kfree(gang[0]);
2425 		}
2426 	}
2427 
2428 	while (1) {
2429 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2430 					     (void **)gang, 0,
2431 					     ARRAY_SIZE(gang));
2432 		if (!ret)
2433 			break;
2434 		for (i = 0; i < ret; i++)
2435 			btrfs_free_fs_root(fs_info, gang[i]);
2436 	}
2437 	return 0;
2438 }
2439 
2440 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2441 {
2442 	u64 root_objectid = 0;
2443 	struct btrfs_root *gang[8];
2444 	int i;
2445 	int ret;
2446 
2447 	while (1) {
2448 		ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2449 					     (void **)gang, root_objectid,
2450 					     ARRAY_SIZE(gang));
2451 		if (!ret)
2452 			break;
2453 
2454 		root_objectid = gang[ret - 1]->root_key.objectid + 1;
2455 		for (i = 0; i < ret; i++) {
2456 			int err;
2457 
2458 			root_objectid = gang[i]->root_key.objectid;
2459 			err = btrfs_orphan_cleanup(gang[i]);
2460 			if (err)
2461 				return err;
2462 		}
2463 		root_objectid++;
2464 	}
2465 	return 0;
2466 }
2467 
2468 int btrfs_commit_super(struct btrfs_root *root)
2469 {
2470 	struct btrfs_trans_handle *trans;
2471 	int ret;
2472 
2473 	mutex_lock(&root->fs_info->cleaner_mutex);
2474 	btrfs_run_delayed_iputs(root);
2475 	btrfs_clean_old_snapshots(root);
2476 	mutex_unlock(&root->fs_info->cleaner_mutex);
2477 
2478 	/* wait until ongoing cleanup work done */
2479 	down_write(&root->fs_info->cleanup_work_sem);
2480 	up_write(&root->fs_info->cleanup_work_sem);
2481 
2482 	trans = btrfs_join_transaction(root);
2483 	if (IS_ERR(trans))
2484 		return PTR_ERR(trans);
2485 	ret = btrfs_commit_transaction(trans, root);
2486 	BUG_ON(ret);
2487 	/* run commit again to drop the original snapshot */
2488 	trans = btrfs_join_transaction(root);
2489 	if (IS_ERR(trans))
2490 		return PTR_ERR(trans);
2491 	btrfs_commit_transaction(trans, root);
2492 	ret = btrfs_write_and_wait_transaction(NULL, root);
2493 	BUG_ON(ret);
2494 
2495 	ret = write_ctree_super(NULL, root, 0);
2496 	return ret;
2497 }
2498 
2499 int close_ctree(struct btrfs_root *root)
2500 {
2501 	struct btrfs_fs_info *fs_info = root->fs_info;
2502 	int ret;
2503 
2504 	fs_info->closing = 1;
2505 	smp_mb();
2506 
2507 	btrfs_scrub_cancel(root);
2508 
2509 	/* wait for any defraggers to finish */
2510 	wait_event(fs_info->transaction_wait,
2511 		   (atomic_read(&fs_info->defrag_running) == 0));
2512 
2513 	/* clear out the rbtree of defraggable inodes */
2514 	btrfs_run_defrag_inodes(root->fs_info);
2515 
2516 	btrfs_put_block_group_cache(fs_info);
2517 
2518 	/*
2519 	 * Here come 2 situations when btrfs is broken to flip readonly:
2520 	 *
2521 	 * 1. when btrfs flips readonly somewhere else before
2522 	 * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
2523 	 * and btrfs will skip to write sb directly to keep
2524 	 * ERROR state on disk.
2525 	 *
2526 	 * 2. when btrfs flips readonly just in btrfs_commit_super,
2527 	 * and in such case, btrfs cannot write sb via btrfs_commit_super,
2528 	 * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
2529 	 * btrfs will cleanup all FS resources first and write sb then.
2530 	 */
2531 	if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2532 		ret = btrfs_commit_super(root);
2533 		if (ret)
2534 			printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2535 	}
2536 
2537 	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
2538 		ret = btrfs_error_commit_super(root);
2539 		if (ret)
2540 			printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2541 	}
2542 
2543 	kthread_stop(root->fs_info->transaction_kthread);
2544 	kthread_stop(root->fs_info->cleaner_kthread);
2545 
2546 	fs_info->closing = 2;
2547 	smp_mb();
2548 
2549 	if (fs_info->delalloc_bytes) {
2550 		printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2551 		       (unsigned long long)fs_info->delalloc_bytes);
2552 	}
2553 	if (fs_info->total_ref_cache_size) {
2554 		printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2555 		       (unsigned long long)fs_info->total_ref_cache_size);
2556 	}
2557 
2558 	free_extent_buffer(fs_info->extent_root->node);
2559 	free_extent_buffer(fs_info->extent_root->commit_root);
2560 	free_extent_buffer(fs_info->tree_root->node);
2561 	free_extent_buffer(fs_info->tree_root->commit_root);
2562 	free_extent_buffer(root->fs_info->chunk_root->node);
2563 	free_extent_buffer(root->fs_info->chunk_root->commit_root);
2564 	free_extent_buffer(root->fs_info->dev_root->node);
2565 	free_extent_buffer(root->fs_info->dev_root->commit_root);
2566 	free_extent_buffer(root->fs_info->csum_root->node);
2567 	free_extent_buffer(root->fs_info->csum_root->commit_root);
2568 
2569 	btrfs_free_block_groups(root->fs_info);
2570 
2571 	del_fs_roots(fs_info);
2572 
2573 	iput(fs_info->btree_inode);
2574 	kfree(fs_info->delayed_root);
2575 
2576 	btrfs_stop_workers(&fs_info->generic_worker);
2577 	btrfs_stop_workers(&fs_info->fixup_workers);
2578 	btrfs_stop_workers(&fs_info->delalloc_workers);
2579 	btrfs_stop_workers(&fs_info->workers);
2580 	btrfs_stop_workers(&fs_info->endio_workers);
2581 	btrfs_stop_workers(&fs_info->endio_meta_workers);
2582 	btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2583 	btrfs_stop_workers(&fs_info->endio_write_workers);
2584 	btrfs_stop_workers(&fs_info->endio_freespace_worker);
2585 	btrfs_stop_workers(&fs_info->submit_workers);
2586 	btrfs_stop_workers(&fs_info->delayed_workers);
2587 
2588 	btrfs_close_devices(fs_info->fs_devices);
2589 	btrfs_mapping_tree_free(&fs_info->mapping_tree);
2590 
2591 	bdi_destroy(&fs_info->bdi);
2592 	cleanup_srcu_struct(&fs_info->subvol_srcu);
2593 
2594 	kfree(fs_info->extent_root);
2595 	kfree(fs_info->tree_root);
2596 	kfree(fs_info->chunk_root);
2597 	kfree(fs_info->dev_root);
2598 	kfree(fs_info->csum_root);
2599 	kfree(fs_info);
2600 
2601 	return 0;
2602 }
2603 
2604 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2605 {
2606 	int ret;
2607 	struct inode *btree_inode = buf->first_page->mapping->host;
2608 
2609 	ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
2610 				     NULL);
2611 	if (!ret)
2612 		return ret;
2613 
2614 	ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2615 				    parent_transid);
2616 	return !ret;
2617 }
2618 
2619 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2620 {
2621 	struct inode *btree_inode = buf->first_page->mapping->host;
2622 	return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2623 					  buf);
2624 }
2625 
2626 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2627 {
2628 	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2629 	u64 transid = btrfs_header_generation(buf);
2630 	struct inode *btree_inode = root->fs_info->btree_inode;
2631 	int was_dirty;
2632 
2633 	btrfs_assert_tree_locked(buf);
2634 	if (transid != root->fs_info->generation) {
2635 		printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2636 		       "found %llu running %llu\n",
2637 			(unsigned long long)buf->start,
2638 			(unsigned long long)transid,
2639 			(unsigned long long)root->fs_info->generation);
2640 		WARN_ON(1);
2641 	}
2642 	was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2643 					    buf);
2644 	if (!was_dirty) {
2645 		spin_lock(&root->fs_info->delalloc_lock);
2646 		root->fs_info->dirty_metadata_bytes += buf->len;
2647 		spin_unlock(&root->fs_info->delalloc_lock);
2648 	}
2649 }
2650 
2651 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2652 {
2653 	/*
2654 	 * looks as though older kernels can get into trouble with
2655 	 * this code, they end up stuck in balance_dirty_pages forever
2656 	 */
2657 	u64 num_dirty;
2658 	unsigned long thresh = 32 * 1024 * 1024;
2659 
2660 	if (current->flags & PF_MEMALLOC)
2661 		return;
2662 
2663 	btrfs_balance_delayed_items(root);
2664 
2665 	num_dirty = root->fs_info->dirty_metadata_bytes;
2666 
2667 	if (num_dirty > thresh) {
2668 		balance_dirty_pages_ratelimited_nr(
2669 				   root->fs_info->btree_inode->i_mapping, 1);
2670 	}
2671 	return;
2672 }
2673 
2674 void __btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2675 {
2676 	/*
2677 	 * looks as though older kernels can get into trouble with
2678 	 * this code, they end up stuck in balance_dirty_pages forever
2679 	 */
2680 	u64 num_dirty;
2681 	unsigned long thresh = 32 * 1024 * 1024;
2682 
2683 	if (current->flags & PF_MEMALLOC)
2684 		return;
2685 
2686 	num_dirty = root->fs_info->dirty_metadata_bytes;
2687 
2688 	if (num_dirty > thresh) {
2689 		balance_dirty_pages_ratelimited_nr(
2690 				   root->fs_info->btree_inode->i_mapping, 1);
2691 	}
2692 	return;
2693 }
2694 
2695 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2696 {
2697 	struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2698 	int ret;
2699 	ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2700 	if (ret == 0)
2701 		set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2702 	return ret;
2703 }
2704 
2705 int btree_lock_page_hook(struct page *page)
2706 {
2707 	struct inode *inode = page->mapping->host;
2708 	struct btrfs_root *root = BTRFS_I(inode)->root;
2709 	struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2710 	struct extent_buffer *eb;
2711 	unsigned long len;
2712 	u64 bytenr = page_offset(page);
2713 
2714 	if (page->private == EXTENT_PAGE_PRIVATE)
2715 		goto out;
2716 
2717 	len = page->private >> 2;
2718 	eb = find_extent_buffer(io_tree, bytenr, len);
2719 	if (!eb)
2720 		goto out;
2721 
2722 	btrfs_tree_lock(eb);
2723 	btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2724 
2725 	if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2726 		spin_lock(&root->fs_info->delalloc_lock);
2727 		if (root->fs_info->dirty_metadata_bytes >= eb->len)
2728 			root->fs_info->dirty_metadata_bytes -= eb->len;
2729 		else
2730 			WARN_ON(1);
2731 		spin_unlock(&root->fs_info->delalloc_lock);
2732 	}
2733 
2734 	btrfs_tree_unlock(eb);
2735 	free_extent_buffer(eb);
2736 out:
2737 	lock_page(page);
2738 	return 0;
2739 }
2740 
2741 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
2742 			      int read_only)
2743 {
2744 	if (read_only)
2745 		return;
2746 
2747 	if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
2748 		printk(KERN_WARNING "warning: mount fs with errors, "
2749 		       "running btrfsck is recommended\n");
2750 }
2751 
2752 int btrfs_error_commit_super(struct btrfs_root *root)
2753 {
2754 	int ret;
2755 
2756 	mutex_lock(&root->fs_info->cleaner_mutex);
2757 	btrfs_run_delayed_iputs(root);
2758 	mutex_unlock(&root->fs_info->cleaner_mutex);
2759 
2760 	down_write(&root->fs_info->cleanup_work_sem);
2761 	up_write(&root->fs_info->cleanup_work_sem);
2762 
2763 	/* cleanup FS via transaction */
2764 	btrfs_cleanup_transaction(root);
2765 
2766 	ret = write_ctree_super(NULL, root, 0);
2767 
2768 	return ret;
2769 }
2770 
2771 static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
2772 {
2773 	struct btrfs_inode *btrfs_inode;
2774 	struct list_head splice;
2775 
2776 	INIT_LIST_HEAD(&splice);
2777 
2778 	mutex_lock(&root->fs_info->ordered_operations_mutex);
2779 	spin_lock(&root->fs_info->ordered_extent_lock);
2780 
2781 	list_splice_init(&root->fs_info->ordered_operations, &splice);
2782 	while (!list_empty(&splice)) {
2783 		btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2784 					 ordered_operations);
2785 
2786 		list_del_init(&btrfs_inode->ordered_operations);
2787 
2788 		btrfs_invalidate_inodes(btrfs_inode->root);
2789 	}
2790 
2791 	spin_unlock(&root->fs_info->ordered_extent_lock);
2792 	mutex_unlock(&root->fs_info->ordered_operations_mutex);
2793 
2794 	return 0;
2795 }
2796 
2797 static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
2798 {
2799 	struct list_head splice;
2800 	struct btrfs_ordered_extent *ordered;
2801 	struct inode *inode;
2802 
2803 	INIT_LIST_HEAD(&splice);
2804 
2805 	spin_lock(&root->fs_info->ordered_extent_lock);
2806 
2807 	list_splice_init(&root->fs_info->ordered_extents, &splice);
2808 	while (!list_empty(&splice)) {
2809 		ordered = list_entry(splice.next, struct btrfs_ordered_extent,
2810 				     root_extent_list);
2811 
2812 		list_del_init(&ordered->root_extent_list);
2813 		atomic_inc(&ordered->refs);
2814 
2815 		/* the inode may be getting freed (in sys_unlink path). */
2816 		inode = igrab(ordered->inode);
2817 
2818 		spin_unlock(&root->fs_info->ordered_extent_lock);
2819 		if (inode)
2820 			iput(inode);
2821 
2822 		atomic_set(&ordered->refs, 1);
2823 		btrfs_put_ordered_extent(ordered);
2824 
2825 		spin_lock(&root->fs_info->ordered_extent_lock);
2826 	}
2827 
2828 	spin_unlock(&root->fs_info->ordered_extent_lock);
2829 
2830 	return 0;
2831 }
2832 
2833 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
2834 				      struct btrfs_root *root)
2835 {
2836 	struct rb_node *node;
2837 	struct btrfs_delayed_ref_root *delayed_refs;
2838 	struct btrfs_delayed_ref_node *ref;
2839 	int ret = 0;
2840 
2841 	delayed_refs = &trans->delayed_refs;
2842 
2843 	spin_lock(&delayed_refs->lock);
2844 	if (delayed_refs->num_entries == 0) {
2845 		spin_unlock(&delayed_refs->lock);
2846 		printk(KERN_INFO "delayed_refs has NO entry\n");
2847 		return ret;
2848 	}
2849 
2850 	node = rb_first(&delayed_refs->root);
2851 	while (node) {
2852 		ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
2853 		node = rb_next(node);
2854 
2855 		ref->in_tree = 0;
2856 		rb_erase(&ref->rb_node, &delayed_refs->root);
2857 		delayed_refs->num_entries--;
2858 
2859 		atomic_set(&ref->refs, 1);
2860 		if (btrfs_delayed_ref_is_head(ref)) {
2861 			struct btrfs_delayed_ref_head *head;
2862 
2863 			head = btrfs_delayed_node_to_head(ref);
2864 			mutex_lock(&head->mutex);
2865 			kfree(head->extent_op);
2866 			delayed_refs->num_heads--;
2867 			if (list_empty(&head->cluster))
2868 				delayed_refs->num_heads_ready--;
2869 			list_del_init(&head->cluster);
2870 			mutex_unlock(&head->mutex);
2871 		}
2872 
2873 		spin_unlock(&delayed_refs->lock);
2874 		btrfs_put_delayed_ref(ref);
2875 
2876 		cond_resched();
2877 		spin_lock(&delayed_refs->lock);
2878 	}
2879 
2880 	spin_unlock(&delayed_refs->lock);
2881 
2882 	return ret;
2883 }
2884 
2885 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
2886 {
2887 	struct btrfs_pending_snapshot *snapshot;
2888 	struct list_head splice;
2889 
2890 	INIT_LIST_HEAD(&splice);
2891 
2892 	list_splice_init(&t->pending_snapshots, &splice);
2893 
2894 	while (!list_empty(&splice)) {
2895 		snapshot = list_entry(splice.next,
2896 				      struct btrfs_pending_snapshot,
2897 				      list);
2898 
2899 		list_del_init(&snapshot->list);
2900 
2901 		kfree(snapshot);
2902 	}
2903 
2904 	return 0;
2905 }
2906 
2907 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root)
2908 {
2909 	struct btrfs_inode *btrfs_inode;
2910 	struct list_head splice;
2911 
2912 	INIT_LIST_HEAD(&splice);
2913 
2914 	list_splice_init(&root->fs_info->delalloc_inodes, &splice);
2915 
2916 	spin_lock(&root->fs_info->delalloc_lock);
2917 
2918 	while (!list_empty(&splice)) {
2919 		btrfs_inode = list_entry(splice.next, struct btrfs_inode,
2920 				    delalloc_inodes);
2921 
2922 		list_del_init(&btrfs_inode->delalloc_inodes);
2923 
2924 		btrfs_invalidate_inodes(btrfs_inode->root);
2925 	}
2926 
2927 	spin_unlock(&root->fs_info->delalloc_lock);
2928 
2929 	return 0;
2930 }
2931 
2932 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
2933 					struct extent_io_tree *dirty_pages,
2934 					int mark)
2935 {
2936 	int ret;
2937 	struct page *page;
2938 	struct inode *btree_inode = root->fs_info->btree_inode;
2939 	struct extent_buffer *eb;
2940 	u64 start = 0;
2941 	u64 end;
2942 	u64 offset;
2943 	unsigned long index;
2944 
2945 	while (1) {
2946 		ret = find_first_extent_bit(dirty_pages, start, &start, &end,
2947 					    mark);
2948 		if (ret)
2949 			break;
2950 
2951 		clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
2952 		while (start <= end) {
2953 			index = start >> PAGE_CACHE_SHIFT;
2954 			start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
2955 			page = find_get_page(btree_inode->i_mapping, index);
2956 			if (!page)
2957 				continue;
2958 			offset = page_offset(page);
2959 
2960 			spin_lock(&dirty_pages->buffer_lock);
2961 			eb = radix_tree_lookup(
2962 			     &(&BTRFS_I(page->mapping->host)->io_tree)->buffer,
2963 					       offset >> PAGE_CACHE_SHIFT);
2964 			spin_unlock(&dirty_pages->buffer_lock);
2965 			if (eb) {
2966 				ret = test_and_clear_bit(EXTENT_BUFFER_DIRTY,
2967 							 &eb->bflags);
2968 				atomic_set(&eb->refs, 1);
2969 			}
2970 			if (PageWriteback(page))
2971 				end_page_writeback(page);
2972 
2973 			lock_page(page);
2974 			if (PageDirty(page)) {
2975 				clear_page_dirty_for_io(page);
2976 				spin_lock_irq(&page->mapping->tree_lock);
2977 				radix_tree_tag_clear(&page->mapping->page_tree,
2978 							page_index(page),
2979 							PAGECACHE_TAG_DIRTY);
2980 				spin_unlock_irq(&page->mapping->tree_lock);
2981 			}
2982 
2983 			page->mapping->a_ops->invalidatepage(page, 0);
2984 			unlock_page(page);
2985 		}
2986 	}
2987 
2988 	return ret;
2989 }
2990 
2991 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
2992 				       struct extent_io_tree *pinned_extents)
2993 {
2994 	struct extent_io_tree *unpin;
2995 	u64 start;
2996 	u64 end;
2997 	int ret;
2998 
2999 	unpin = pinned_extents;
3000 	while (1) {
3001 		ret = find_first_extent_bit(unpin, 0, &start, &end,
3002 					    EXTENT_DIRTY);
3003 		if (ret)
3004 			break;
3005 
3006 		/* opt_discard */
3007 		if (btrfs_test_opt(root, DISCARD))
3008 			ret = btrfs_error_discard_extent(root, start,
3009 							 end + 1 - start,
3010 							 NULL);
3011 
3012 		clear_extent_dirty(unpin, start, end, GFP_NOFS);
3013 		btrfs_error_unpin_extent_range(root, start, end);
3014 		cond_resched();
3015 	}
3016 
3017 	return 0;
3018 }
3019 
3020 static int btrfs_cleanup_transaction(struct btrfs_root *root)
3021 {
3022 	struct btrfs_transaction *t;
3023 	LIST_HEAD(list);
3024 
3025 	WARN_ON(1);
3026 
3027 	mutex_lock(&root->fs_info->transaction_kthread_mutex);
3028 
3029 	spin_lock(&root->fs_info->trans_lock);
3030 	list_splice_init(&root->fs_info->trans_list, &list);
3031 	root->fs_info->trans_no_join = 1;
3032 	spin_unlock(&root->fs_info->trans_lock);
3033 
3034 	while (!list_empty(&list)) {
3035 		t = list_entry(list.next, struct btrfs_transaction, list);
3036 		if (!t)
3037 			break;
3038 
3039 		btrfs_destroy_ordered_operations(root);
3040 
3041 		btrfs_destroy_ordered_extents(root);
3042 
3043 		btrfs_destroy_delayed_refs(t, root);
3044 
3045 		btrfs_block_rsv_release(root,
3046 					&root->fs_info->trans_block_rsv,
3047 					t->dirty_pages.dirty_bytes);
3048 
3049 		/* FIXME: cleanup wait for commit */
3050 		t->in_commit = 1;
3051 		t->blocked = 1;
3052 		if (waitqueue_active(&root->fs_info->transaction_blocked_wait))
3053 			wake_up(&root->fs_info->transaction_blocked_wait);
3054 
3055 		t->blocked = 0;
3056 		if (waitqueue_active(&root->fs_info->transaction_wait))
3057 			wake_up(&root->fs_info->transaction_wait);
3058 
3059 		t->commit_done = 1;
3060 		if (waitqueue_active(&t->commit_wait))
3061 			wake_up(&t->commit_wait);
3062 
3063 		btrfs_destroy_pending_snapshots(t);
3064 
3065 		btrfs_destroy_delalloc_inodes(root);
3066 
3067 		spin_lock(&root->fs_info->trans_lock);
3068 		root->fs_info->running_transaction = NULL;
3069 		spin_unlock(&root->fs_info->trans_lock);
3070 
3071 		btrfs_destroy_marked_extents(root, &t->dirty_pages,
3072 					     EXTENT_DIRTY);
3073 
3074 		btrfs_destroy_pinned_extent(root,
3075 					    root->fs_info->pinned_extents);
3076 
3077 		atomic_set(&t->use_count, 0);
3078 		list_del_init(&t->list);
3079 		memset(t, 0, sizeof(*t));
3080 		kmem_cache_free(btrfs_transaction_cachep, t);
3081 	}
3082 
3083 	spin_lock(&root->fs_info->trans_lock);
3084 	root->fs_info->trans_no_join = 0;
3085 	spin_unlock(&root->fs_info->trans_lock);
3086 	mutex_unlock(&root->fs_info->transaction_kthread_mutex);
3087 
3088 	return 0;
3089 }
3090 
3091 static struct extent_io_ops btree_extent_io_ops = {
3092 	.write_cache_pages_lock_hook = btree_lock_page_hook,
3093 	.readpage_end_io_hook = btree_readpage_end_io_hook,
3094 	.submit_bio_hook = btree_submit_bio_hook,
3095 	/* note we're sharing with inode.c for the merge bio hook */
3096 	.merge_bio_hook = btrfs_merge_bio_hook,
3097 };
3098