Btrfs: setup blank root and fs_info for mount time
[linux-3.10.git] / fs / btrfs / disk-io.c
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 "compat.h"
33 #include "ctree.h"
34 #include "disk-io.h"
35 #include "transaction.h"
36 #include "btrfs_inode.h"
37 #include "volumes.h"
38 #include "print-tree.h"
39 #include "async-thread.h"
40 #include "locking.h"
41 #include "tree-log.h"
42 #include "free-space-cache.h"
43
44 static struct extent_io_ops btree_extent_io_ops;
45 static void end_workqueue_fn(struct btrfs_work *work);
46 static void free_fs_root(struct btrfs_root *root);
47
48 /*
49  * end_io_wq structs are used to do processing in task context when an IO is
50  * complete.  This is used during reads to verify checksums, and it is used
51  * by writes to insert metadata for new file extents after IO is complete.
52  */
53 struct end_io_wq {
54         struct bio *bio;
55         bio_end_io_t *end_io;
56         void *private;
57         struct btrfs_fs_info *info;
58         int error;
59         int metadata;
60         struct list_head list;
61         struct btrfs_work work;
62 };
63
64 /*
65  * async submit bios are used to offload expensive checksumming
66  * onto the worker threads.  They checksum file and metadata bios
67  * just before they are sent down the IO stack.
68  */
69 struct async_submit_bio {
70         struct inode *inode;
71         struct bio *bio;
72         struct list_head list;
73         extent_submit_bio_hook_t *submit_bio_start;
74         extent_submit_bio_hook_t *submit_bio_done;
75         int rw;
76         int mirror_num;
77         unsigned long bio_flags;
78         /*
79          * bio_offset is optional, can be used if the pages in the bio
80          * can't tell us where in the file the bio should go
81          */
82         u64 bio_offset;
83         struct btrfs_work work;
84 };
85
86 /* These are used to set the lockdep class on the extent buffer locks.
87  * The class is set by the readpage_end_io_hook after the buffer has
88  * passed csum validation but before the pages are unlocked.
89  *
90  * The lockdep class is also set by btrfs_init_new_buffer on freshly
91  * allocated blocks.
92  *
93  * The class is based on the level in the tree block, which allows lockdep
94  * to know that lower nodes nest inside the locks of higher nodes.
95  *
96  * We also add a check to make sure the highest level of the tree is
97  * the same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this
98  * code needs update as well.
99  */
100 #ifdef CONFIG_DEBUG_LOCK_ALLOC
101 # if BTRFS_MAX_LEVEL != 8
102 #  error
103 # endif
104 static struct lock_class_key btrfs_eb_class[BTRFS_MAX_LEVEL + 1];
105 static const char *btrfs_eb_name[BTRFS_MAX_LEVEL + 1] = {
106         /* leaf */
107         "btrfs-extent-00",
108         "btrfs-extent-01",
109         "btrfs-extent-02",
110         "btrfs-extent-03",
111         "btrfs-extent-04",
112         "btrfs-extent-05",
113         "btrfs-extent-06",
114         "btrfs-extent-07",
115         /* highest possible level */
116         "btrfs-extent-08",
117 };
118 #endif
119
120 /*
121  * extents on the btree inode are pretty simple, there's one extent
122  * that covers the entire device
123  */
124 static struct extent_map *btree_get_extent(struct inode *inode,
125                 struct page *page, size_t page_offset, u64 start, u64 len,
126                 int create)
127 {
128         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
129         struct extent_map *em;
130         int ret;
131
132         read_lock(&em_tree->lock);
133         em = lookup_extent_mapping(em_tree, start, len);
134         if (em) {
135                 em->bdev =
136                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
137                 read_unlock(&em_tree->lock);
138                 goto out;
139         }
140         read_unlock(&em_tree->lock);
141
142         em = alloc_extent_map(GFP_NOFS);
143         if (!em) {
144                 em = ERR_PTR(-ENOMEM);
145                 goto out;
146         }
147         em->start = 0;
148         em->len = (u64)-1;
149         em->block_len = (u64)-1;
150         em->block_start = 0;
151         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
152
153         write_lock(&em_tree->lock);
154         ret = add_extent_mapping(em_tree, em);
155         if (ret == -EEXIST) {
156                 u64 failed_start = em->start;
157                 u64 failed_len = em->len;
158
159                 free_extent_map(em);
160                 em = lookup_extent_mapping(em_tree, start, len);
161                 if (em) {
162                         ret = 0;
163                 } else {
164                         em = lookup_extent_mapping(em_tree, failed_start,
165                                                    failed_len);
166                         ret = -EIO;
167                 }
168         } else if (ret) {
169                 free_extent_map(em);
170                 em = NULL;
171         }
172         write_unlock(&em_tree->lock);
173
174         if (ret)
175                 em = ERR_PTR(ret);
176 out:
177         return em;
178 }
179
180 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
181 {
182         return crc32c(seed, data, len);
183 }
184
185 void btrfs_csum_final(u32 crc, char *result)
186 {
187         *(__le32 *)result = ~cpu_to_le32(crc);
188 }
189
190 /*
191  * compute the csum for a btree block, and either verify it or write it
192  * into the csum field of the block.
193  */
194 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
195                            int verify)
196 {
197         u16 csum_size =
198                 btrfs_super_csum_size(&root->fs_info->super_copy);
199         char *result = NULL;
200         unsigned long len;
201         unsigned long cur_len;
202         unsigned long offset = BTRFS_CSUM_SIZE;
203         char *map_token = NULL;
204         char *kaddr;
205         unsigned long map_start;
206         unsigned long map_len;
207         int err;
208         u32 crc = ~(u32)0;
209         unsigned long inline_result;
210
211         len = buf->len - offset;
212         while (len > 0) {
213                 err = map_private_extent_buffer(buf, offset, 32,
214                                         &map_token, &kaddr,
215                                         &map_start, &map_len, KM_USER0);
216                 if (err)
217                         return 1;
218                 cur_len = min(len, map_len - (offset - map_start));
219                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
220                                       crc, cur_len);
221                 len -= cur_len;
222                 offset += cur_len;
223                 unmap_extent_buffer(buf, map_token, KM_USER0);
224         }
225         if (csum_size > sizeof(inline_result)) {
226                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
227                 if (!result)
228                         return 1;
229         } else {
230                 result = (char *)&inline_result;
231         }
232
233         btrfs_csum_final(crc, result);
234
235         if (verify) {
236                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
237                         u32 val;
238                         u32 found = 0;
239                         memcpy(&found, result, csum_size);
240
241                         read_extent_buffer(buf, &val, 0, csum_size);
242                         if (printk_ratelimit()) {
243                                 printk(KERN_INFO "btrfs: %s checksum verify "
244                                        "failed on %llu wanted %X found %X "
245                                        "level %d\n",
246                                        root->fs_info->sb->s_id,
247                                        (unsigned long long)buf->start, val, found,
248                                        btrfs_header_level(buf));
249                         }
250                         if (result != (char *)&inline_result)
251                                 kfree(result);
252                         return 1;
253                 }
254         } else {
255                 write_extent_buffer(buf, result, 0, csum_size);
256         }
257         if (result != (char *)&inline_result)
258                 kfree(result);
259         return 0;
260 }
261
262 /*
263  * we can't consider a given block up to date unless the transid of the
264  * block matches the transid in the parent node's pointer.  This is how we
265  * detect blocks that either didn't get written at all or got written
266  * in the wrong place.
267  */
268 static int verify_parent_transid(struct extent_io_tree *io_tree,
269                                  struct extent_buffer *eb, u64 parent_transid)
270 {
271         struct extent_state *cached_state = NULL;
272         int ret;
273
274         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
275                 return 0;
276
277         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
278                          0, &cached_state, GFP_NOFS);
279         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
280             btrfs_header_generation(eb) == parent_transid) {
281                 ret = 0;
282                 goto out;
283         }
284         if (printk_ratelimit()) {
285                 printk("parent transid verify failed on %llu wanted %llu "
286                        "found %llu\n",
287                        (unsigned long long)eb->start,
288                        (unsigned long long)parent_transid,
289                        (unsigned long long)btrfs_header_generation(eb));
290         }
291         ret = 1;
292         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
293 out:
294         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
295                              &cached_state, GFP_NOFS);
296         return ret;
297 }
298
299 /*
300  * helper to read a given tree block, doing retries as required when
301  * the checksums don't match and we have alternate mirrors to try.
302  */
303 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
304                                           struct extent_buffer *eb,
305                                           u64 start, u64 parent_transid)
306 {
307         struct extent_io_tree *io_tree;
308         int ret;
309         int num_copies = 0;
310         int mirror_num = 0;
311
312         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
313         while (1) {
314                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
315                                                btree_get_extent, mirror_num);
316                 if (!ret &&
317                     !verify_parent_transid(io_tree, eb, parent_transid))
318                         return ret;
319
320                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
321                                               eb->start, eb->len);
322                 if (num_copies == 1)
323                         return ret;
324
325                 mirror_num++;
326                 if (mirror_num > num_copies)
327                         return ret;
328         }
329         return -EIO;
330 }
331
332 /*
333  * checksum a dirty tree block before IO.  This has extra checks to make sure
334  * we only fill in the checksum field in the first page of a multi-page block
335  */
336
337 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
338 {
339         struct extent_io_tree *tree;
340         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
341         u64 found_start;
342         unsigned long len;
343         struct extent_buffer *eb;
344         int ret;
345
346         tree = &BTRFS_I(page->mapping->host)->io_tree;
347
348         if (page->private == EXTENT_PAGE_PRIVATE)
349                 goto out;
350         if (!page->private)
351                 goto out;
352         len = page->private >> 2;
353         WARN_ON(len == 0);
354
355         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
356         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
357                                              btrfs_header_generation(eb));
358         BUG_ON(ret);
359         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
360
361         found_start = btrfs_header_bytenr(eb);
362         if (found_start != start) {
363                 WARN_ON(1);
364                 goto err;
365         }
366         if (eb->first_page != page) {
367                 WARN_ON(1);
368                 goto err;
369         }
370         if (!PageUptodate(page)) {
371                 WARN_ON(1);
372                 goto err;
373         }
374         csum_tree_block(root, eb, 0);
375 err:
376         free_extent_buffer(eb);
377 out:
378         return 0;
379 }
380
381 static int check_tree_block_fsid(struct btrfs_root *root,
382                                  struct extent_buffer *eb)
383 {
384         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
385         u8 fsid[BTRFS_UUID_SIZE];
386         int ret = 1;
387
388         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
389                            BTRFS_FSID_SIZE);
390         while (fs_devices) {
391                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
392                         ret = 0;
393                         break;
394                 }
395                 fs_devices = fs_devices->seed;
396         }
397         return ret;
398 }
399
400 #ifdef CONFIG_DEBUG_LOCK_ALLOC
401 void btrfs_set_buffer_lockdep_class(struct extent_buffer *eb, int level)
402 {
403         lockdep_set_class_and_name(&eb->lock,
404                            &btrfs_eb_class[level],
405                            btrfs_eb_name[level]);
406 }
407 #endif
408
409 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
410                                struct extent_state *state)
411 {
412         struct extent_io_tree *tree;
413         u64 found_start;
414         int found_level;
415         unsigned long len;
416         struct extent_buffer *eb;
417         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
418         int ret = 0;
419
420         tree = &BTRFS_I(page->mapping->host)->io_tree;
421         if (page->private == EXTENT_PAGE_PRIVATE)
422                 goto out;
423         if (!page->private)
424                 goto out;
425
426         len = page->private >> 2;
427         WARN_ON(len == 0);
428
429         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
430
431         found_start = btrfs_header_bytenr(eb);
432         if (found_start != start) {
433                 if (printk_ratelimit()) {
434                         printk(KERN_INFO "btrfs bad tree block start "
435                                "%llu %llu\n",
436                                (unsigned long long)found_start,
437                                (unsigned long long)eb->start);
438                 }
439                 ret = -EIO;
440                 goto err;
441         }
442         if (eb->first_page != page) {
443                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
444                        eb->first_page->index, page->index);
445                 WARN_ON(1);
446                 ret = -EIO;
447                 goto err;
448         }
449         if (check_tree_block_fsid(root, eb)) {
450                 if (printk_ratelimit()) {
451                         printk(KERN_INFO "btrfs bad fsid on block %llu\n",
452                                (unsigned long long)eb->start);
453                 }
454                 ret = -EIO;
455                 goto err;
456         }
457         found_level = btrfs_header_level(eb);
458
459         btrfs_set_buffer_lockdep_class(eb, found_level);
460
461         ret = csum_tree_block(root, eb, 1);
462         if (ret)
463                 ret = -EIO;
464
465         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
466         end = eb->start + end - 1;
467 err:
468         free_extent_buffer(eb);
469 out:
470         return ret;
471 }
472
473 static void end_workqueue_bio(struct bio *bio, int err)
474 {
475         struct end_io_wq *end_io_wq = bio->bi_private;
476         struct btrfs_fs_info *fs_info;
477
478         fs_info = end_io_wq->info;
479         end_io_wq->error = err;
480         end_io_wq->work.func = end_workqueue_fn;
481         end_io_wq->work.flags = 0;
482
483         if (bio->bi_rw & REQ_WRITE) {
484                 if (end_io_wq->metadata == 1)
485                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
486                                            &end_io_wq->work);
487                 else if (end_io_wq->metadata == 2)
488                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
489                                            &end_io_wq->work);
490                 else
491                         btrfs_queue_worker(&fs_info->endio_write_workers,
492                                            &end_io_wq->work);
493         } else {
494                 if (end_io_wq->metadata)
495                         btrfs_queue_worker(&fs_info->endio_meta_workers,
496                                            &end_io_wq->work);
497                 else
498                         btrfs_queue_worker(&fs_info->endio_workers,
499                                            &end_io_wq->work);
500         }
501 }
502
503 /*
504  * For the metadata arg you want
505  *
506  * 0 - if data
507  * 1 - if normal metadta
508  * 2 - if writing to the free space cache area
509  */
510 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
511                         int metadata)
512 {
513         struct end_io_wq *end_io_wq;
514         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
515         if (!end_io_wq)
516                 return -ENOMEM;
517
518         end_io_wq->private = bio->bi_private;
519         end_io_wq->end_io = bio->bi_end_io;
520         end_io_wq->info = info;
521         end_io_wq->error = 0;
522         end_io_wq->bio = bio;
523         end_io_wq->metadata = metadata;
524
525         bio->bi_private = end_io_wq;
526         bio->bi_end_io = end_workqueue_bio;
527         return 0;
528 }
529
530 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
531 {
532         unsigned long limit = min_t(unsigned long,
533                                     info->workers.max_workers,
534                                     info->fs_devices->open_devices);
535         return 256 * limit;
536 }
537
538 int btrfs_congested_async(struct btrfs_fs_info *info, int iodone)
539 {
540         return atomic_read(&info->nr_async_bios) >
541                 btrfs_async_submit_limit(info);
542 }
543
544 static void run_one_async_start(struct btrfs_work *work)
545 {
546         struct async_submit_bio *async;
547
548         async = container_of(work, struct  async_submit_bio, work);
549         async->submit_bio_start(async->inode, async->rw, async->bio,
550                                async->mirror_num, async->bio_flags,
551                                async->bio_offset);
552 }
553
554 static void run_one_async_done(struct btrfs_work *work)
555 {
556         struct btrfs_fs_info *fs_info;
557         struct async_submit_bio *async;
558         int limit;
559
560         async = container_of(work, struct  async_submit_bio, work);
561         fs_info = BTRFS_I(async->inode)->root->fs_info;
562
563         limit = btrfs_async_submit_limit(fs_info);
564         limit = limit * 2 / 3;
565
566         atomic_dec(&fs_info->nr_async_submits);
567
568         if (atomic_read(&fs_info->nr_async_submits) < limit &&
569             waitqueue_active(&fs_info->async_submit_wait))
570                 wake_up(&fs_info->async_submit_wait);
571
572         async->submit_bio_done(async->inode, async->rw, async->bio,
573                                async->mirror_num, async->bio_flags,
574                                async->bio_offset);
575 }
576
577 static void run_one_async_free(struct btrfs_work *work)
578 {
579         struct async_submit_bio *async;
580
581         async = container_of(work, struct  async_submit_bio, work);
582         kfree(async);
583 }
584
585 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
586                         int rw, struct bio *bio, int mirror_num,
587                         unsigned long bio_flags,
588                         u64 bio_offset,
589                         extent_submit_bio_hook_t *submit_bio_start,
590                         extent_submit_bio_hook_t *submit_bio_done)
591 {
592         struct async_submit_bio *async;
593
594         async = kmalloc(sizeof(*async), GFP_NOFS);
595         if (!async)
596                 return -ENOMEM;
597
598         async->inode = inode;
599         async->rw = rw;
600         async->bio = bio;
601         async->mirror_num = mirror_num;
602         async->submit_bio_start = submit_bio_start;
603         async->submit_bio_done = submit_bio_done;
604
605         async->work.func = run_one_async_start;
606         async->work.ordered_func = run_one_async_done;
607         async->work.ordered_free = run_one_async_free;
608
609         async->work.flags = 0;
610         async->bio_flags = bio_flags;
611         async->bio_offset = bio_offset;
612
613         atomic_inc(&fs_info->nr_async_submits);
614
615         if (rw & REQ_SYNC)
616                 btrfs_set_work_high_prio(&async->work);
617
618         btrfs_queue_worker(&fs_info->workers, &async->work);
619
620         while (atomic_read(&fs_info->async_submit_draining) &&
621               atomic_read(&fs_info->nr_async_submits)) {
622                 wait_event(fs_info->async_submit_wait,
623                            (atomic_read(&fs_info->nr_async_submits) == 0));
624         }
625
626         return 0;
627 }
628
629 static int btree_csum_one_bio(struct bio *bio)
630 {
631         struct bio_vec *bvec = bio->bi_io_vec;
632         int bio_index = 0;
633         struct btrfs_root *root;
634
635         WARN_ON(bio->bi_vcnt <= 0);
636         while (bio_index < bio->bi_vcnt) {
637                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
638                 csum_dirty_buffer(root, bvec->bv_page);
639                 bio_index++;
640                 bvec++;
641         }
642         return 0;
643 }
644
645 static int __btree_submit_bio_start(struct inode *inode, int rw,
646                                     struct bio *bio, int mirror_num,
647                                     unsigned long bio_flags,
648                                     u64 bio_offset)
649 {
650         /*
651          * when we're called for a write, we're already in the async
652          * submission context.  Just jump into btrfs_map_bio
653          */
654         btree_csum_one_bio(bio);
655         return 0;
656 }
657
658 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
659                                  int mirror_num, unsigned long bio_flags,
660                                  u64 bio_offset)
661 {
662         /*
663          * when we're called for a write, we're already in the async
664          * submission context.  Just jump into btrfs_map_bio
665          */
666         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
667 }
668
669 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
670                                  int mirror_num, unsigned long bio_flags,
671                                  u64 bio_offset)
672 {
673         int ret;
674
675         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
676                                           bio, 1);
677         BUG_ON(ret);
678
679         if (!(rw & REQ_WRITE)) {
680                 /*
681                  * called for a read, do the setup so that checksum validation
682                  * can happen in the async kernel threads
683                  */
684                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
685                                      mirror_num, 0);
686         }
687
688         /*
689          * kthread helpers are used to submit writes so that checksumming
690          * can happen in parallel across all CPUs
691          */
692         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
693                                    inode, rw, bio, mirror_num, 0,
694                                    bio_offset,
695                                    __btree_submit_bio_start,
696                                    __btree_submit_bio_done);
697 }
698
699 static int btree_migratepage(struct address_space *mapping,
700                         struct page *newpage, struct page *page)
701 {
702         /*
703          * we can't safely write a btree page from here,
704          * we haven't done the locking hook
705          */
706         if (PageDirty(page))
707                 return -EAGAIN;
708         /*
709          * Buffers may be managed in a filesystem specific way.
710          * We must have no buffers or drop them.
711          */
712         if (page_has_private(page) &&
713             !try_to_release_page(page, GFP_KERNEL))
714                 return -EAGAIN;
715
716         return migrate_page(mapping, newpage, page);
717 }
718
719 static int btree_writepage(struct page *page, struct writeback_control *wbc)
720 {
721         struct extent_io_tree *tree;
722         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
723         struct extent_buffer *eb;
724         int was_dirty;
725
726         tree = &BTRFS_I(page->mapping->host)->io_tree;
727         if (!(current->flags & PF_MEMALLOC)) {
728                 return extent_write_full_page(tree, page,
729                                               btree_get_extent, wbc);
730         }
731
732         redirty_page_for_writepage(wbc, page);
733         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
734         WARN_ON(!eb);
735
736         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
737         if (!was_dirty) {
738                 spin_lock(&root->fs_info->delalloc_lock);
739                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
740                 spin_unlock(&root->fs_info->delalloc_lock);
741         }
742         free_extent_buffer(eb);
743
744         unlock_page(page);
745         return 0;
746 }
747
748 static int btree_writepages(struct address_space *mapping,
749                             struct writeback_control *wbc)
750 {
751         struct extent_io_tree *tree;
752         tree = &BTRFS_I(mapping->host)->io_tree;
753         if (wbc->sync_mode == WB_SYNC_NONE) {
754                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
755                 u64 num_dirty;
756                 unsigned long thresh = 32 * 1024 * 1024;
757
758                 if (wbc->for_kupdate)
759                         return 0;
760
761                 /* this is a bit racy, but that's ok */
762                 num_dirty = root->fs_info->dirty_metadata_bytes;
763                 if (num_dirty < thresh)
764                         return 0;
765         }
766         return extent_writepages(tree, mapping, btree_get_extent, wbc);
767 }
768
769 static int btree_readpage(struct file *file, struct page *page)
770 {
771         struct extent_io_tree *tree;
772         tree = &BTRFS_I(page->mapping->host)->io_tree;
773         return extent_read_full_page(tree, page, btree_get_extent);
774 }
775
776 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
777 {
778         struct extent_io_tree *tree;
779         struct extent_map_tree *map;
780         int ret;
781
782         if (PageWriteback(page) || PageDirty(page))
783                 return 0;
784
785         tree = &BTRFS_I(page->mapping->host)->io_tree;
786         map = &BTRFS_I(page->mapping->host)->extent_tree;
787
788         ret = try_release_extent_state(map, tree, page, gfp_flags);
789         if (!ret)
790                 return 0;
791
792         ret = try_release_extent_buffer(tree, page);
793         if (ret == 1) {
794                 ClearPagePrivate(page);
795                 set_page_private(page, 0);
796                 page_cache_release(page);
797         }
798
799         return ret;
800 }
801
802 static void btree_invalidatepage(struct page *page, unsigned long offset)
803 {
804         struct extent_io_tree *tree;
805         tree = &BTRFS_I(page->mapping->host)->io_tree;
806         extent_invalidatepage(tree, page, offset);
807         btree_releasepage(page, GFP_NOFS);
808         if (PagePrivate(page)) {
809                 printk(KERN_WARNING "btrfs warning page private not zero "
810                        "on page %llu\n", (unsigned long long)page_offset(page));
811                 ClearPagePrivate(page);
812                 set_page_private(page, 0);
813                 page_cache_release(page);
814         }
815 }
816
817 static const struct address_space_operations btree_aops = {
818         .readpage       = btree_readpage,
819         .writepage      = btree_writepage,
820         .writepages     = btree_writepages,
821         .releasepage    = btree_releasepage,
822         .invalidatepage = btree_invalidatepage,
823         .sync_page      = block_sync_page,
824         .migratepage    = btree_migratepage,
825 };
826
827 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
828                          u64 parent_transid)
829 {
830         struct extent_buffer *buf = NULL;
831         struct inode *btree_inode = root->fs_info->btree_inode;
832         int ret = 0;
833
834         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
835         if (!buf)
836                 return 0;
837         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
838                                  buf, 0, 0, btree_get_extent, 0);
839         free_extent_buffer(buf);
840         return ret;
841 }
842
843 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
844                                             u64 bytenr, u32 blocksize)
845 {
846         struct inode *btree_inode = root->fs_info->btree_inode;
847         struct extent_buffer *eb;
848         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
849                                 bytenr, blocksize, GFP_NOFS);
850         return eb;
851 }
852
853 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
854                                                  u64 bytenr, u32 blocksize)
855 {
856         struct inode *btree_inode = root->fs_info->btree_inode;
857         struct extent_buffer *eb;
858
859         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
860                                  bytenr, blocksize, NULL, GFP_NOFS);
861         return eb;
862 }
863
864
865 int btrfs_write_tree_block(struct extent_buffer *buf)
866 {
867         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
868                                         buf->start + buf->len - 1);
869 }
870
871 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
872 {
873         return filemap_fdatawait_range(buf->first_page->mapping,
874                                        buf->start, buf->start + buf->len - 1);
875 }
876
877 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
878                                       u32 blocksize, u64 parent_transid)
879 {
880         struct extent_buffer *buf = NULL;
881         int ret;
882
883         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
884         if (!buf)
885                 return NULL;
886
887         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
888
889         if (ret == 0)
890                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
891         return buf;
892
893 }
894
895 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
896                      struct extent_buffer *buf)
897 {
898         struct inode *btree_inode = root->fs_info->btree_inode;
899         if (btrfs_header_generation(buf) ==
900             root->fs_info->running_transaction->transid) {
901                 btrfs_assert_tree_locked(buf);
902
903                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
904                         spin_lock(&root->fs_info->delalloc_lock);
905                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
906                                 root->fs_info->dirty_metadata_bytes -= buf->len;
907                         else
908                                 WARN_ON(1);
909                         spin_unlock(&root->fs_info->delalloc_lock);
910                 }
911
912                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
913                 btrfs_set_lock_blocking(buf);
914                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
915                                           buf);
916         }
917         return 0;
918 }
919
920 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
921                         u32 stripesize, struct btrfs_root *root,
922                         struct btrfs_fs_info *fs_info,
923                         u64 objectid)
924 {
925         root->node = NULL;
926         root->commit_root = NULL;
927         root->sectorsize = sectorsize;
928         root->nodesize = nodesize;
929         root->leafsize = leafsize;
930         root->stripesize = stripesize;
931         root->ref_cows = 0;
932         root->track_dirty = 0;
933         root->in_radix = 0;
934         root->orphan_item_inserted = 0;
935         root->orphan_cleanup_state = 0;
936
937         root->fs_info = fs_info;
938         root->objectid = objectid;
939         root->last_trans = 0;
940         root->highest_objectid = 0;
941         root->name = NULL;
942         root->in_sysfs = 0;
943         root->inode_tree = RB_ROOT;
944         root->block_rsv = NULL;
945         root->orphan_block_rsv = NULL;
946
947         INIT_LIST_HEAD(&root->dirty_list);
948         INIT_LIST_HEAD(&root->orphan_list);
949         INIT_LIST_HEAD(&root->root_list);
950         spin_lock_init(&root->node_lock);
951         spin_lock_init(&root->orphan_lock);
952         spin_lock_init(&root->inode_lock);
953         spin_lock_init(&root->accounting_lock);
954         mutex_init(&root->objectid_mutex);
955         mutex_init(&root->log_mutex);
956         init_waitqueue_head(&root->log_writer_wait);
957         init_waitqueue_head(&root->log_commit_wait[0]);
958         init_waitqueue_head(&root->log_commit_wait[1]);
959         atomic_set(&root->log_commit[0], 0);
960         atomic_set(&root->log_commit[1], 0);
961         atomic_set(&root->log_writers, 0);
962         root->log_batch = 0;
963         root->log_transid = 0;
964         root->last_log_commit = 0;
965         extent_io_tree_init(&root->dirty_log_pages,
966                              fs_info->btree_inode->i_mapping, GFP_NOFS);
967
968         memset(&root->root_key, 0, sizeof(root->root_key));
969         memset(&root->root_item, 0, sizeof(root->root_item));
970         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
971         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
972         root->defrag_trans_start = fs_info->generation;
973         init_completion(&root->kobj_unregister);
974         root->defrag_running = 0;
975         root->root_key.objectid = objectid;
976         root->anon_super.s_root = NULL;
977         root->anon_super.s_dev = 0;
978         INIT_LIST_HEAD(&root->anon_super.s_list);
979         INIT_LIST_HEAD(&root->anon_super.s_instances);
980         init_rwsem(&root->anon_super.s_umount);
981
982         return 0;
983 }
984
985 static int find_and_setup_root(struct btrfs_root *tree_root,
986                                struct btrfs_fs_info *fs_info,
987                                u64 objectid,
988                                struct btrfs_root *root)
989 {
990         int ret;
991         u32 blocksize;
992         u64 generation;
993
994         __setup_root(tree_root->nodesize, tree_root->leafsize,
995                      tree_root->sectorsize, tree_root->stripesize,
996                      root, fs_info, objectid);
997         ret = btrfs_find_last_root(tree_root, objectid,
998                                    &root->root_item, &root->root_key);
999         if (ret > 0)
1000                 return -ENOENT;
1001         BUG_ON(ret);
1002
1003         generation = btrfs_root_generation(&root->root_item);
1004         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1005         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1006                                      blocksize, generation);
1007         BUG_ON(!root->node);
1008         root->commit_root = btrfs_root_node(root);
1009         return 0;
1010 }
1011
1012 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1013                                          struct btrfs_fs_info *fs_info)
1014 {
1015         struct btrfs_root *root;
1016         struct btrfs_root *tree_root = fs_info->tree_root;
1017         struct extent_buffer *leaf;
1018
1019         root = kzalloc(sizeof(*root), GFP_NOFS);
1020         if (!root)
1021                 return ERR_PTR(-ENOMEM);
1022
1023         __setup_root(tree_root->nodesize, tree_root->leafsize,
1024                      tree_root->sectorsize, tree_root->stripesize,
1025                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1026
1027         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1028         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1029         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1030         /*
1031          * log trees do not get reference counted because they go away
1032          * before a real commit is actually done.  They do store pointers
1033          * to file data extents, and those reference counts still get
1034          * updated (along with back refs to the log tree).
1035          */
1036         root->ref_cows = 0;
1037
1038         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1039                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1040         if (IS_ERR(leaf)) {
1041                 kfree(root);
1042                 return ERR_CAST(leaf);
1043         }
1044
1045         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1046         btrfs_set_header_bytenr(leaf, leaf->start);
1047         btrfs_set_header_generation(leaf, trans->transid);
1048         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1049         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1050         root->node = leaf;
1051
1052         write_extent_buffer(root->node, root->fs_info->fsid,
1053                             (unsigned long)btrfs_header_fsid(root->node),
1054                             BTRFS_FSID_SIZE);
1055         btrfs_mark_buffer_dirty(root->node);
1056         btrfs_tree_unlock(root->node);
1057         return root;
1058 }
1059
1060 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1061                              struct btrfs_fs_info *fs_info)
1062 {
1063         struct btrfs_root *log_root;
1064
1065         log_root = alloc_log_tree(trans, fs_info);
1066         if (IS_ERR(log_root))
1067                 return PTR_ERR(log_root);
1068         WARN_ON(fs_info->log_root_tree);
1069         fs_info->log_root_tree = log_root;
1070         return 0;
1071 }
1072
1073 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1074                        struct btrfs_root *root)
1075 {
1076         struct btrfs_root *log_root;
1077         struct btrfs_inode_item *inode_item;
1078
1079         log_root = alloc_log_tree(trans, root->fs_info);
1080         if (IS_ERR(log_root))
1081                 return PTR_ERR(log_root);
1082
1083         log_root->last_trans = trans->transid;
1084         log_root->root_key.offset = root->root_key.objectid;
1085
1086         inode_item = &log_root->root_item.inode;
1087         inode_item->generation = cpu_to_le64(1);
1088         inode_item->size = cpu_to_le64(3);
1089         inode_item->nlink = cpu_to_le32(1);
1090         inode_item->nbytes = cpu_to_le64(root->leafsize);
1091         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1092
1093         btrfs_set_root_node(&log_root->root_item, log_root->node);
1094
1095         WARN_ON(root->log_root);
1096         root->log_root = log_root;
1097         root->log_transid = 0;
1098         root->last_log_commit = 0;
1099         return 0;
1100 }
1101
1102 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1103                                                struct btrfs_key *location)
1104 {
1105         struct btrfs_root *root;
1106         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1107         struct btrfs_path *path;
1108         struct extent_buffer *l;
1109         u64 generation;
1110         u32 blocksize;
1111         int ret = 0;
1112
1113         root = kzalloc(sizeof(*root), GFP_NOFS);
1114         if (!root)
1115                 return ERR_PTR(-ENOMEM);
1116         if (location->offset == (u64)-1) {
1117                 ret = find_and_setup_root(tree_root, fs_info,
1118                                           location->objectid, root);
1119                 if (ret) {
1120                         kfree(root);
1121                         return ERR_PTR(ret);
1122                 }
1123                 goto out;
1124         }
1125
1126         __setup_root(tree_root->nodesize, tree_root->leafsize,
1127                      tree_root->sectorsize, tree_root->stripesize,
1128                      root, fs_info, location->objectid);
1129
1130         path = btrfs_alloc_path();
1131         BUG_ON(!path);
1132         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1133         if (ret == 0) {
1134                 l = path->nodes[0];
1135                 read_extent_buffer(l, &root->root_item,
1136                                 btrfs_item_ptr_offset(l, path->slots[0]),
1137                                 sizeof(root->root_item));
1138                 memcpy(&root->root_key, location, sizeof(*location));
1139         }
1140         btrfs_free_path(path);
1141         if (ret) {
1142                 if (ret > 0)
1143                         ret = -ENOENT;
1144                 return ERR_PTR(ret);
1145         }
1146
1147         generation = btrfs_root_generation(&root->root_item);
1148         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1149         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1150                                      blocksize, generation);
1151         root->commit_root = btrfs_root_node(root);
1152         BUG_ON(!root->node);
1153 out:
1154         if (location->objectid != BTRFS_TREE_LOG_OBJECTID)
1155                 root->ref_cows = 1;
1156
1157         return root;
1158 }
1159
1160 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
1161                                         u64 root_objectid)
1162 {
1163         struct btrfs_root *root;
1164
1165         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
1166                 return fs_info->tree_root;
1167         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
1168                 return fs_info->extent_root;
1169
1170         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1171                                  (unsigned long)root_objectid);
1172         return root;
1173 }
1174
1175 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1176                                               struct btrfs_key *location)
1177 {
1178         struct btrfs_root *root;
1179         int ret;
1180
1181         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1182                 return fs_info->tree_root;
1183         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1184                 return fs_info->extent_root;
1185         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1186                 return fs_info->chunk_root;
1187         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1188                 return fs_info->dev_root;
1189         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1190                 return fs_info->csum_root;
1191 again:
1192         spin_lock(&fs_info->fs_roots_radix_lock);
1193         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1194                                  (unsigned long)location->objectid);
1195         spin_unlock(&fs_info->fs_roots_radix_lock);
1196         if (root)
1197                 return root;
1198
1199         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1200         if (IS_ERR(root))
1201                 return root;
1202
1203         set_anon_super(&root->anon_super, NULL);
1204
1205         if (btrfs_root_refs(&root->root_item) == 0) {
1206                 ret = -ENOENT;
1207                 goto fail;
1208         }
1209
1210         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1211         if (ret < 0)
1212                 goto fail;
1213         if (ret == 0)
1214                 root->orphan_item_inserted = 1;
1215
1216         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1217         if (ret)
1218                 goto fail;
1219
1220         spin_lock(&fs_info->fs_roots_radix_lock);
1221         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1222                                 (unsigned long)root->root_key.objectid,
1223                                 root);
1224         if (ret == 0)
1225                 root->in_radix = 1;
1226
1227         spin_unlock(&fs_info->fs_roots_radix_lock);
1228         radix_tree_preload_end();
1229         if (ret) {
1230                 if (ret == -EEXIST) {
1231                         free_fs_root(root);
1232                         goto again;
1233                 }
1234                 goto fail;
1235         }
1236
1237         ret = btrfs_find_dead_roots(fs_info->tree_root,
1238                                     root->root_key.objectid);
1239         WARN_ON(ret);
1240         return root;
1241 fail:
1242         free_fs_root(root);
1243         return ERR_PTR(ret);
1244 }
1245
1246 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
1247                                       struct btrfs_key *location,
1248                                       const char *name, int namelen)
1249 {
1250         return btrfs_read_fs_root_no_name(fs_info, location);
1251 #if 0
1252         struct btrfs_root *root;
1253         int ret;
1254
1255         root = btrfs_read_fs_root_no_name(fs_info, location);
1256         if (!root)
1257                 return NULL;
1258
1259         if (root->in_sysfs)
1260                 return root;
1261
1262         ret = btrfs_set_root_name(root, name, namelen);
1263         if (ret) {
1264                 free_extent_buffer(root->node);
1265                 kfree(root);
1266                 return ERR_PTR(ret);
1267         }
1268
1269         ret = btrfs_sysfs_add_root(root);
1270         if (ret) {
1271                 free_extent_buffer(root->node);
1272                 kfree(root->name);
1273                 kfree(root);
1274                 return ERR_PTR(ret);
1275         }
1276         root->in_sysfs = 1;
1277         return root;
1278 #endif
1279 }
1280
1281 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1282 {
1283         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1284         int ret = 0;
1285         struct btrfs_device *device;
1286         struct backing_dev_info *bdi;
1287
1288         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1289                 if (!device->bdev)
1290                         continue;
1291                 bdi = blk_get_backing_dev_info(device->bdev);
1292                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1293                         ret = 1;
1294                         break;
1295                 }
1296         }
1297         return ret;
1298 }
1299
1300 /*
1301  * this unplugs every device on the box, and it is only used when page
1302  * is null
1303  */
1304 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1305 {
1306         struct btrfs_device *device;
1307         struct btrfs_fs_info *info;
1308
1309         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
1310         list_for_each_entry(device, &info->fs_devices->devices, dev_list) {
1311                 if (!device->bdev)
1312                         continue;
1313
1314                 bdi = blk_get_backing_dev_info(device->bdev);
1315                 if (bdi->unplug_io_fn)
1316                         bdi->unplug_io_fn(bdi, page);
1317         }
1318 }
1319
1320 static void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
1321 {
1322         struct inode *inode;
1323         struct extent_map_tree *em_tree;
1324         struct extent_map *em;
1325         struct address_space *mapping;
1326         u64 offset;
1327
1328         /* the generic O_DIRECT read code does this */
1329         if (1 || !page) {
1330                 __unplug_io_fn(bdi, page);
1331                 return;
1332         }
1333
1334         /*
1335          * page->mapping may change at any time.  Get a consistent copy
1336          * and use that for everything below
1337          */
1338         smp_mb();
1339         mapping = page->mapping;
1340         if (!mapping)
1341                 return;
1342
1343         inode = mapping->host;
1344
1345         /*
1346          * don't do the expensive searching for a small number of
1347          * devices
1348          */
1349         if (BTRFS_I(inode)->root->fs_info->fs_devices->open_devices <= 2) {
1350                 __unplug_io_fn(bdi, page);
1351                 return;
1352         }
1353
1354         offset = page_offset(page);
1355
1356         em_tree = &BTRFS_I(inode)->extent_tree;
1357         read_lock(&em_tree->lock);
1358         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1359         read_unlock(&em_tree->lock);
1360         if (!em) {
1361                 __unplug_io_fn(bdi, page);
1362                 return;
1363         }
1364
1365         if (em->block_start >= EXTENT_MAP_LAST_BYTE) {
1366                 free_extent_map(em);
1367                 __unplug_io_fn(bdi, page);
1368                 return;
1369         }
1370         offset = offset - em->start;
1371         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1372                           em->block_start + offset, page);
1373         free_extent_map(em);
1374 }
1375
1376 /*
1377  * If this fails, caller must call bdi_destroy() to get rid of the
1378  * bdi again.
1379  */
1380 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1381 {
1382         int err;
1383
1384         bdi->capabilities = BDI_CAP_MAP_COPY;
1385         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1386         if (err)
1387                 return err;
1388
1389         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1390         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1391         bdi->unplug_io_data     = info;
1392         bdi->congested_fn       = btrfs_congested_fn;
1393         bdi->congested_data     = info;
1394         return 0;
1395 }
1396
1397 static int bio_ready_for_csum(struct bio *bio)
1398 {
1399         u64 length = 0;
1400         u64 buf_len = 0;
1401         u64 start = 0;
1402         struct page *page;
1403         struct extent_io_tree *io_tree = NULL;
1404         struct bio_vec *bvec;
1405         int i;
1406         int ret;
1407
1408         bio_for_each_segment(bvec, bio, i) {
1409                 page = bvec->bv_page;
1410                 if (page->private == EXTENT_PAGE_PRIVATE) {
1411                         length += bvec->bv_len;
1412                         continue;
1413                 }
1414                 if (!page->private) {
1415                         length += bvec->bv_len;
1416                         continue;
1417                 }
1418                 length = bvec->bv_len;
1419                 buf_len = page->private >> 2;
1420                 start = page_offset(page) + bvec->bv_offset;
1421                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1422         }
1423         /* are we fully contained in this bio? */
1424         if (buf_len <= length)
1425                 return 1;
1426
1427         ret = extent_range_uptodate(io_tree, start + length,
1428                                     start + buf_len - 1);
1429         return ret;
1430 }
1431
1432 /*
1433  * called by the kthread helper functions to finally call the bio end_io
1434  * functions.  This is where read checksum verification actually happens
1435  */
1436 static void end_workqueue_fn(struct btrfs_work *work)
1437 {
1438         struct bio *bio;
1439         struct end_io_wq *end_io_wq;
1440         struct btrfs_fs_info *fs_info;
1441         int error;
1442
1443         end_io_wq = container_of(work, struct end_io_wq, work);
1444         bio = end_io_wq->bio;
1445         fs_info = end_io_wq->info;
1446
1447         /* metadata bio reads are special because the whole tree block must
1448          * be checksummed at once.  This makes sure the entire block is in
1449          * ram and up to date before trying to verify things.  For
1450          * blocksize <= pagesize, it is basically a noop
1451          */
1452         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1453             !bio_ready_for_csum(bio)) {
1454                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1455                                    &end_io_wq->work);
1456                 return;
1457         }
1458         error = end_io_wq->error;
1459         bio->bi_private = end_io_wq->private;
1460         bio->bi_end_io = end_io_wq->end_io;
1461         kfree(end_io_wq);
1462         bio_endio(bio, error);
1463 }
1464
1465 static int cleaner_kthread(void *arg)
1466 {
1467         struct btrfs_root *root = arg;
1468
1469         do {
1470                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1471
1472                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1473                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1474                         btrfs_run_delayed_iputs(root);
1475                         btrfs_clean_old_snapshots(root);
1476                         mutex_unlock(&root->fs_info->cleaner_mutex);
1477                 }
1478
1479                 if (freezing(current)) {
1480                         refrigerator();
1481                 } else {
1482                         set_current_state(TASK_INTERRUPTIBLE);
1483                         if (!kthread_should_stop())
1484                                 schedule();
1485                         __set_current_state(TASK_RUNNING);
1486                 }
1487         } while (!kthread_should_stop());
1488         return 0;
1489 }
1490
1491 static int transaction_kthread(void *arg)
1492 {
1493         struct btrfs_root *root = arg;
1494         struct btrfs_trans_handle *trans;
1495         struct btrfs_transaction *cur;
1496         u64 transid;
1497         unsigned long now;
1498         unsigned long delay;
1499         int ret;
1500
1501         do {
1502                 delay = HZ * 30;
1503                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1504                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1505
1506                 spin_lock(&root->fs_info->new_trans_lock);
1507                 cur = root->fs_info->running_transaction;
1508                 if (!cur) {
1509                         spin_unlock(&root->fs_info->new_trans_lock);
1510                         goto sleep;
1511                 }
1512
1513                 now = get_seconds();
1514                 if (!cur->blocked &&
1515                     (now < cur->start_time || now - cur->start_time < 30)) {
1516                         spin_unlock(&root->fs_info->new_trans_lock);
1517                         delay = HZ * 5;
1518                         goto sleep;
1519                 }
1520                 transid = cur->transid;
1521                 spin_unlock(&root->fs_info->new_trans_lock);
1522
1523                 trans = btrfs_join_transaction(root, 1);
1524                 if (transid == trans->transid) {
1525                         ret = btrfs_commit_transaction(trans, root);
1526                         BUG_ON(ret);
1527                 } else {
1528                         btrfs_end_transaction(trans, root);
1529                 }
1530 sleep:
1531                 wake_up_process(root->fs_info->cleaner_kthread);
1532                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1533
1534                 if (freezing(current)) {
1535                         refrigerator();
1536                 } else {
1537                         set_current_state(TASK_INTERRUPTIBLE);
1538                         if (!kthread_should_stop() &&
1539                             !btrfs_transaction_blocked(root->fs_info))
1540                                 schedule_timeout(delay);
1541                         __set_current_state(TASK_RUNNING);
1542                 }
1543         } while (!kthread_should_stop());
1544         return 0;
1545 }
1546
1547 struct btrfs_root *open_ctree(struct super_block *sb,
1548                               struct btrfs_fs_devices *fs_devices,
1549                               char *options)
1550 {
1551         u32 sectorsize;
1552         u32 nodesize;
1553         u32 leafsize;
1554         u32 blocksize;
1555         u32 stripesize;
1556         u64 generation;
1557         u64 features;
1558         struct btrfs_key location;
1559         struct buffer_head *bh;
1560         struct btrfs_root *extent_root = kzalloc(sizeof(struct btrfs_root),
1561                                                  GFP_NOFS);
1562         struct btrfs_root *csum_root = kzalloc(sizeof(struct btrfs_root),
1563                                                  GFP_NOFS);
1564         struct btrfs_root *tree_root = btrfs_sb(sb);
1565         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1566         struct btrfs_root *chunk_root = kzalloc(sizeof(struct btrfs_root),
1567                                                 GFP_NOFS);
1568         struct btrfs_root *dev_root = kzalloc(sizeof(struct btrfs_root),
1569                                               GFP_NOFS);
1570         struct btrfs_root *log_tree_root;
1571
1572         int ret;
1573         int err = -EINVAL;
1574
1575         struct btrfs_super_block *disk_super;
1576
1577         if (!extent_root || !tree_root || !fs_info ||
1578             !chunk_root || !dev_root || !csum_root) {
1579                 err = -ENOMEM;
1580                 goto fail;
1581         }
1582
1583         ret = init_srcu_struct(&fs_info->subvol_srcu);
1584         if (ret) {
1585                 err = ret;
1586                 goto fail;
1587         }
1588
1589         ret = setup_bdi(fs_info, &fs_info->bdi);
1590         if (ret) {
1591                 err = ret;
1592                 goto fail_srcu;
1593         }
1594
1595         fs_info->btree_inode = new_inode(sb);
1596         if (!fs_info->btree_inode) {
1597                 err = -ENOMEM;
1598                 goto fail_bdi;
1599         }
1600
1601         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1602         INIT_LIST_HEAD(&fs_info->trans_list);
1603         INIT_LIST_HEAD(&fs_info->dead_roots);
1604         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1605         INIT_LIST_HEAD(&fs_info->hashers);
1606         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1607         INIT_LIST_HEAD(&fs_info->ordered_operations);
1608         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1609         spin_lock_init(&fs_info->delalloc_lock);
1610         spin_lock_init(&fs_info->new_trans_lock);
1611         spin_lock_init(&fs_info->ref_cache_lock);
1612         spin_lock_init(&fs_info->fs_roots_radix_lock);
1613         spin_lock_init(&fs_info->delayed_iput_lock);
1614
1615         init_completion(&fs_info->kobj_unregister);
1616         fs_info->tree_root = tree_root;
1617         fs_info->extent_root = extent_root;
1618         fs_info->csum_root = csum_root;
1619         fs_info->chunk_root = chunk_root;
1620         fs_info->dev_root = dev_root;
1621         fs_info->fs_devices = fs_devices;
1622         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1623         INIT_LIST_HEAD(&fs_info->space_info);
1624         btrfs_mapping_init(&fs_info->mapping_tree);
1625         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1626         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1627         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1628         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1629         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1630         INIT_LIST_HEAD(&fs_info->durable_block_rsv_list);
1631         mutex_init(&fs_info->durable_block_rsv_mutex);
1632         atomic_set(&fs_info->nr_async_submits, 0);
1633         atomic_set(&fs_info->async_delalloc_pages, 0);
1634         atomic_set(&fs_info->async_submit_draining, 0);
1635         atomic_set(&fs_info->nr_async_bios, 0);
1636         fs_info->sb = sb;
1637         fs_info->max_inline = 8192 * 1024;
1638         fs_info->metadata_ratio = 0;
1639
1640         fs_info->thread_pool_size = min_t(unsigned long,
1641                                           num_online_cpus() + 2, 8);
1642
1643         INIT_LIST_HEAD(&fs_info->ordered_extents);
1644         spin_lock_init(&fs_info->ordered_extent_lock);
1645
1646         sb->s_blocksize = 4096;
1647         sb->s_blocksize_bits = blksize_bits(4096);
1648         sb->s_bdi = &fs_info->bdi;
1649
1650         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
1651         fs_info->btree_inode->i_nlink = 1;
1652         /*
1653          * we set the i_size on the btree inode to the max possible int.
1654          * the real end of the address space is determined by all of
1655          * the devices in the system
1656          */
1657         fs_info->btree_inode->i_size = OFFSET_MAX;
1658         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1659         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1660
1661         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
1662         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1663                              fs_info->btree_inode->i_mapping,
1664                              GFP_NOFS);
1665         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1666                              GFP_NOFS);
1667
1668         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1669
1670         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1671         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1672                sizeof(struct btrfs_key));
1673         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
1674         insert_inode_hash(fs_info->btree_inode);
1675
1676         spin_lock_init(&fs_info->block_group_cache_lock);
1677         fs_info->block_group_cache_tree = RB_ROOT;
1678
1679         extent_io_tree_init(&fs_info->freed_extents[0],
1680                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1681         extent_io_tree_init(&fs_info->freed_extents[1],
1682                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1683         fs_info->pinned_extents = &fs_info->freed_extents[0];
1684         fs_info->do_barriers = 1;
1685
1686
1687         mutex_init(&fs_info->trans_mutex);
1688         mutex_init(&fs_info->ordered_operations_mutex);
1689         mutex_init(&fs_info->tree_log_mutex);
1690         mutex_init(&fs_info->chunk_mutex);
1691         mutex_init(&fs_info->transaction_kthread_mutex);
1692         mutex_init(&fs_info->cleaner_mutex);
1693         mutex_init(&fs_info->volume_mutex);
1694         init_rwsem(&fs_info->extent_commit_sem);
1695         init_rwsem(&fs_info->cleanup_work_sem);
1696         init_rwsem(&fs_info->subvol_sem);
1697
1698         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
1699         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
1700
1701         init_waitqueue_head(&fs_info->transaction_throttle);
1702         init_waitqueue_head(&fs_info->transaction_wait);
1703         init_waitqueue_head(&fs_info->transaction_blocked_wait);
1704         init_waitqueue_head(&fs_info->async_submit_wait);
1705
1706         __setup_root(4096, 4096, 4096, 4096, tree_root,
1707                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1708
1709         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
1710         if (!bh)
1711                 goto fail_iput;
1712
1713         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1714         memcpy(&fs_info->super_for_commit, &fs_info->super_copy,
1715                sizeof(fs_info->super_for_commit));
1716         brelse(bh);
1717
1718         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1719
1720         disk_super = &fs_info->super_copy;
1721         if (!btrfs_super_root(disk_super))
1722                 goto fail_iput;
1723
1724         ret = btrfs_parse_options(tree_root, options);
1725         if (ret) {
1726                 err = ret;
1727                 goto fail_iput;
1728         }
1729
1730         features = btrfs_super_incompat_flags(disk_super) &
1731                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
1732         if (features) {
1733                 printk(KERN_ERR "BTRFS: couldn't mount because of "
1734                        "unsupported optional features (%Lx).\n",
1735                        (unsigned long long)features);
1736                 err = -EINVAL;
1737                 goto fail_iput;
1738         }
1739
1740         features = btrfs_super_incompat_flags(disk_super);
1741         if (!(features & BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF)) {
1742                 features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
1743                 btrfs_set_super_incompat_flags(disk_super, features);
1744         }
1745
1746         features = btrfs_super_compat_ro_flags(disk_super) &
1747                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
1748         if (!(sb->s_flags & MS_RDONLY) && features) {
1749                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
1750                        "unsupported option features (%Lx).\n",
1751                        (unsigned long long)features);
1752                 err = -EINVAL;
1753                 goto fail_iput;
1754         }
1755
1756         btrfs_init_workers(&fs_info->generic_worker,
1757                            "genwork", 1, NULL);
1758
1759         btrfs_init_workers(&fs_info->workers, "worker",
1760                            fs_info->thread_pool_size,
1761                            &fs_info->generic_worker);
1762
1763         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
1764                            fs_info->thread_pool_size,
1765                            &fs_info->generic_worker);
1766
1767         btrfs_init_workers(&fs_info->submit_workers, "submit",
1768                            min_t(u64, fs_devices->num_devices,
1769                            fs_info->thread_pool_size),
1770                            &fs_info->generic_worker);
1771
1772         /* a higher idle thresh on the submit workers makes it much more
1773          * likely that bios will be send down in a sane order to the
1774          * devices
1775          */
1776         fs_info->submit_workers.idle_thresh = 64;
1777
1778         fs_info->workers.idle_thresh = 16;
1779         fs_info->workers.ordered = 1;
1780
1781         fs_info->delalloc_workers.idle_thresh = 2;
1782         fs_info->delalloc_workers.ordered = 1;
1783
1784         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
1785                            &fs_info->generic_worker);
1786         btrfs_init_workers(&fs_info->endio_workers, "endio",
1787                            fs_info->thread_pool_size,
1788                            &fs_info->generic_worker);
1789         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
1790                            fs_info->thread_pool_size,
1791                            &fs_info->generic_worker);
1792         btrfs_init_workers(&fs_info->endio_meta_write_workers,
1793                            "endio-meta-write", fs_info->thread_pool_size,
1794                            &fs_info->generic_worker);
1795         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
1796                            fs_info->thread_pool_size,
1797                            &fs_info->generic_worker);
1798         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
1799                            1, &fs_info->generic_worker);
1800
1801         /*
1802          * endios are largely parallel and should have a very
1803          * low idle thresh
1804          */
1805         fs_info->endio_workers.idle_thresh = 4;
1806         fs_info->endio_meta_workers.idle_thresh = 4;
1807
1808         fs_info->endio_write_workers.idle_thresh = 2;
1809         fs_info->endio_meta_write_workers.idle_thresh = 2;
1810
1811         btrfs_start_workers(&fs_info->workers, 1);
1812         btrfs_start_workers(&fs_info->generic_worker, 1);
1813         btrfs_start_workers(&fs_info->submit_workers, 1);
1814         btrfs_start_workers(&fs_info->delalloc_workers, 1);
1815         btrfs_start_workers(&fs_info->fixup_workers, 1);
1816         btrfs_start_workers(&fs_info->endio_workers, 1);
1817         btrfs_start_workers(&fs_info->endio_meta_workers, 1);
1818         btrfs_start_workers(&fs_info->endio_meta_write_workers, 1);
1819         btrfs_start_workers(&fs_info->endio_write_workers, 1);
1820         btrfs_start_workers(&fs_info->endio_freespace_worker, 1);
1821
1822         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1823         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
1824                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
1825
1826         nodesize = btrfs_super_nodesize(disk_super);
1827         leafsize = btrfs_super_leafsize(disk_super);
1828         sectorsize = btrfs_super_sectorsize(disk_super);
1829         stripesize = btrfs_super_stripesize(disk_super);
1830         tree_root->nodesize = nodesize;
1831         tree_root->leafsize = leafsize;
1832         tree_root->sectorsize = sectorsize;
1833         tree_root->stripesize = stripesize;
1834
1835         sb->s_blocksize = sectorsize;
1836         sb->s_blocksize_bits = blksize_bits(sectorsize);
1837
1838         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1839                     sizeof(disk_super->magic))) {
1840                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
1841                 goto fail_sb_buffer;
1842         }
1843
1844         mutex_lock(&fs_info->chunk_mutex);
1845         ret = btrfs_read_sys_array(tree_root);
1846         mutex_unlock(&fs_info->chunk_mutex);
1847         if (ret) {
1848                 printk(KERN_WARNING "btrfs: failed to read the system "
1849                        "array on %s\n", sb->s_id);
1850                 goto fail_sb_buffer;
1851         }
1852
1853         blocksize = btrfs_level_size(tree_root,
1854                                      btrfs_super_chunk_root_level(disk_super));
1855         generation = btrfs_super_chunk_root_generation(disk_super);
1856
1857         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1858                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1859
1860         chunk_root->node = read_tree_block(chunk_root,
1861                                            btrfs_super_chunk_root(disk_super),
1862                                            blocksize, generation);
1863         BUG_ON(!chunk_root->node);
1864         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
1865                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
1866                        sb->s_id);
1867                 goto fail_chunk_root;
1868         }
1869         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
1870         chunk_root->commit_root = btrfs_root_node(chunk_root);
1871
1872         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1873            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1874            BTRFS_UUID_SIZE);
1875
1876         mutex_lock(&fs_info->chunk_mutex);
1877         ret = btrfs_read_chunk_tree(chunk_root);
1878         mutex_unlock(&fs_info->chunk_mutex);
1879         if (ret) {
1880                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
1881                        sb->s_id);
1882                 goto fail_chunk_root;
1883         }
1884
1885         btrfs_close_extra_devices(fs_devices);
1886
1887         blocksize = btrfs_level_size(tree_root,
1888                                      btrfs_super_root_level(disk_super));
1889         generation = btrfs_super_generation(disk_super);
1890
1891         tree_root->node = read_tree_block(tree_root,
1892                                           btrfs_super_root(disk_super),
1893                                           blocksize, generation);
1894         if (!tree_root->node)
1895                 goto fail_chunk_root;
1896         if (!test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
1897                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
1898                        sb->s_id);
1899                 goto fail_tree_root;
1900         }
1901         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
1902         tree_root->commit_root = btrfs_root_node(tree_root);
1903
1904         ret = find_and_setup_root(tree_root, fs_info,
1905                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1906         if (ret)
1907                 goto fail_tree_root;
1908         extent_root->track_dirty = 1;
1909
1910         ret = find_and_setup_root(tree_root, fs_info,
1911                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1912         if (ret)
1913                 goto fail_extent_root;
1914         dev_root->track_dirty = 1;
1915
1916         ret = find_and_setup_root(tree_root, fs_info,
1917                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
1918         if (ret)
1919                 goto fail_dev_root;
1920
1921         csum_root->track_dirty = 1;
1922
1923         fs_info->generation = generation;
1924         fs_info->last_trans_committed = generation;
1925         fs_info->data_alloc_profile = (u64)-1;
1926         fs_info->metadata_alloc_profile = (u64)-1;
1927         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1928
1929         ret = btrfs_read_block_groups(extent_root);
1930         if (ret) {
1931                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
1932                 goto fail_block_groups;
1933         }
1934
1935         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1936                                                "btrfs-cleaner");
1937         if (IS_ERR(fs_info->cleaner_kthread))
1938                 goto fail_block_groups;
1939
1940         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1941                                                    tree_root,
1942                                                    "btrfs-transaction");
1943         if (IS_ERR(fs_info->transaction_kthread))
1944                 goto fail_cleaner;
1945
1946         if (!btrfs_test_opt(tree_root, SSD) &&
1947             !btrfs_test_opt(tree_root, NOSSD) &&
1948             !fs_info->fs_devices->rotating) {
1949                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
1950                        "mode\n");
1951                 btrfs_set_opt(fs_info->mount_opt, SSD);
1952         }
1953
1954         if (btrfs_super_log_root(disk_super) != 0) {
1955                 u64 bytenr = btrfs_super_log_root(disk_super);
1956
1957                 if (fs_devices->rw_devices == 0) {
1958                         printk(KERN_WARNING "Btrfs log replay required "
1959                                "on RO media\n");
1960                         err = -EIO;
1961                         goto fail_trans_kthread;
1962                 }
1963                 blocksize =
1964                      btrfs_level_size(tree_root,
1965                                       btrfs_super_log_root_level(disk_super));
1966
1967                 log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1968                 if (!log_tree_root) {
1969                         err = -ENOMEM;
1970                         goto fail_trans_kthread;
1971                 }
1972
1973                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
1974                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1975
1976                 log_tree_root->node = read_tree_block(tree_root, bytenr,
1977                                                       blocksize,
1978                                                       generation + 1);
1979                 ret = btrfs_recover_log_trees(log_tree_root);
1980                 BUG_ON(ret);
1981
1982                 if (sb->s_flags & MS_RDONLY) {
1983                         ret =  btrfs_commit_super(tree_root);
1984                         BUG_ON(ret);
1985                 }
1986         }
1987
1988         ret = btrfs_find_orphan_roots(tree_root);
1989         BUG_ON(ret);
1990
1991         if (!(sb->s_flags & MS_RDONLY)) {
1992                 ret = btrfs_cleanup_fs_roots(fs_info);
1993                 BUG_ON(ret);
1994
1995                 ret = btrfs_recover_relocation(tree_root);
1996                 if (ret < 0) {
1997                         printk(KERN_WARNING
1998                                "btrfs: failed to recover relocation\n");
1999                         err = -EINVAL;
2000                         goto fail_trans_kthread;
2001                 }
2002         }
2003
2004         location.objectid = BTRFS_FS_TREE_OBJECTID;
2005         location.type = BTRFS_ROOT_ITEM_KEY;
2006         location.offset = (u64)-1;
2007
2008         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2009         if (!fs_info->fs_root)
2010                 goto fail_trans_kthread;
2011         if (IS_ERR(fs_info->fs_root)) {
2012                 err = PTR_ERR(fs_info->fs_root);
2013                 goto fail_trans_kthread;
2014         }
2015
2016         if (!(sb->s_flags & MS_RDONLY)) {
2017                 down_read(&fs_info->cleanup_work_sem);
2018                 btrfs_orphan_cleanup(fs_info->fs_root);
2019                 btrfs_orphan_cleanup(fs_info->tree_root);
2020                 up_read(&fs_info->cleanup_work_sem);
2021         }
2022
2023         return tree_root;
2024
2025 fail_trans_kthread:
2026         kthread_stop(fs_info->transaction_kthread);
2027 fail_cleaner:
2028         kthread_stop(fs_info->cleaner_kthread);
2029
2030         /*
2031          * make sure we're done with the btree inode before we stop our
2032          * kthreads
2033          */
2034         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2035         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2036
2037 fail_block_groups:
2038         btrfs_free_block_groups(fs_info);
2039         free_extent_buffer(csum_root->node);
2040         free_extent_buffer(csum_root->commit_root);
2041 fail_dev_root:
2042         free_extent_buffer(dev_root->node);
2043         free_extent_buffer(dev_root->commit_root);
2044 fail_extent_root:
2045         free_extent_buffer(extent_root->node);
2046         free_extent_buffer(extent_root->commit_root);
2047 fail_tree_root:
2048         free_extent_buffer(tree_root->node);
2049         free_extent_buffer(tree_root->commit_root);
2050 fail_chunk_root:
2051         free_extent_buffer(chunk_root->node);
2052         free_extent_buffer(chunk_root->commit_root);
2053 fail_sb_buffer:
2054         btrfs_stop_workers(&fs_info->generic_worker);
2055         btrfs_stop_workers(&fs_info->fixup_workers);
2056         btrfs_stop_workers(&fs_info->delalloc_workers);
2057         btrfs_stop_workers(&fs_info->workers);
2058         btrfs_stop_workers(&fs_info->endio_workers);
2059         btrfs_stop_workers(&fs_info->endio_meta_workers);
2060         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2061         btrfs_stop_workers(&fs_info->endio_write_workers);
2062         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2063         btrfs_stop_workers(&fs_info->submit_workers);
2064 fail_iput:
2065         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2066         iput(fs_info->btree_inode);
2067
2068         btrfs_close_devices(fs_info->fs_devices);
2069         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2070 fail_bdi:
2071         bdi_destroy(&fs_info->bdi);
2072 fail_srcu:
2073         cleanup_srcu_struct(&fs_info->subvol_srcu);
2074 fail:
2075         kfree(extent_root);
2076         kfree(tree_root);
2077         kfree(fs_info);
2078         kfree(chunk_root);
2079         kfree(dev_root);
2080         kfree(csum_root);
2081         return ERR_PTR(err);
2082 }
2083
2084 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2085 {
2086         char b[BDEVNAME_SIZE];
2087
2088         if (uptodate) {
2089                 set_buffer_uptodate(bh);
2090         } else {
2091                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
2092                         printk(KERN_WARNING "lost page write due to "
2093                                         "I/O error on %s\n",
2094                                        bdevname(bh->b_bdev, b));
2095                 }
2096                 /* note, we dont' set_buffer_write_io_error because we have
2097                  * our own ways of dealing with the IO errors
2098                  */
2099                 clear_buffer_uptodate(bh);
2100         }
2101         unlock_buffer(bh);
2102         put_bh(bh);
2103 }
2104
2105 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2106 {
2107         struct buffer_head *bh;
2108         struct buffer_head *latest = NULL;
2109         struct btrfs_super_block *super;
2110         int i;
2111         u64 transid = 0;
2112         u64 bytenr;
2113
2114         /* we would like to check all the supers, but that would make
2115          * a btrfs mount succeed after a mkfs from a different FS.
2116          * So, we need to add a special mount option to scan for
2117          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2118          */
2119         for (i = 0; i < 1; i++) {
2120                 bytenr = btrfs_sb_offset(i);
2121                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2122                         break;
2123                 bh = __bread(bdev, bytenr / 4096, 4096);
2124                 if (!bh)
2125                         continue;
2126
2127                 super = (struct btrfs_super_block *)bh->b_data;
2128                 if (btrfs_super_bytenr(super) != bytenr ||
2129                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2130                             sizeof(super->magic))) {
2131                         brelse(bh);
2132                         continue;
2133                 }
2134
2135                 if (!latest || btrfs_super_generation(super) > transid) {
2136                         brelse(latest);
2137                         latest = bh;
2138                         transid = btrfs_super_generation(super);
2139                 } else {
2140                         brelse(bh);
2141                 }
2142         }
2143         return latest;
2144 }
2145
2146 /*
2147  * this should be called twice, once with wait == 0 and
2148  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2149  * we write are pinned.
2150  *
2151  * They are released when wait == 1 is done.
2152  * max_mirrors must be the same for both runs, and it indicates how
2153  * many supers on this one device should be written.
2154  *
2155  * max_mirrors == 0 means to write them all.
2156  */
2157 static int write_dev_supers(struct btrfs_device *device,
2158                             struct btrfs_super_block *sb,
2159                             int do_barriers, int wait, int max_mirrors)
2160 {
2161         struct buffer_head *bh;
2162         int i;
2163         int ret;
2164         int errors = 0;
2165         u32 crc;
2166         u64 bytenr;
2167         int last_barrier = 0;
2168
2169         if (max_mirrors == 0)
2170                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2171
2172         /* make sure only the last submit_bh does a barrier */
2173         if (do_barriers) {
2174                 for (i = 0; i < max_mirrors; i++) {
2175                         bytenr = btrfs_sb_offset(i);
2176                         if (bytenr + BTRFS_SUPER_INFO_SIZE >=
2177                             device->total_bytes)
2178                                 break;
2179                         last_barrier = i;
2180                 }
2181         }
2182
2183         for (i = 0; i < max_mirrors; i++) {
2184                 bytenr = btrfs_sb_offset(i);
2185                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2186                         break;
2187
2188                 if (wait) {
2189                         bh = __find_get_block(device->bdev, bytenr / 4096,
2190                                               BTRFS_SUPER_INFO_SIZE);
2191                         BUG_ON(!bh);
2192                         wait_on_buffer(bh);
2193                         if (!buffer_uptodate(bh))
2194                                 errors++;
2195
2196                         /* drop our reference */
2197                         brelse(bh);
2198
2199                         /* drop the reference from the wait == 0 run */
2200                         brelse(bh);
2201                         continue;
2202                 } else {
2203                         btrfs_set_super_bytenr(sb, bytenr);
2204
2205                         crc = ~(u32)0;
2206                         crc = btrfs_csum_data(NULL, (char *)sb +
2207                                               BTRFS_CSUM_SIZE, crc,
2208                                               BTRFS_SUPER_INFO_SIZE -
2209                                               BTRFS_CSUM_SIZE);
2210                         btrfs_csum_final(crc, sb->csum);
2211
2212                         /*
2213                          * one reference for us, and we leave it for the
2214                          * caller
2215                          */
2216                         bh = __getblk(device->bdev, bytenr / 4096,
2217                                       BTRFS_SUPER_INFO_SIZE);
2218                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2219
2220                         /* one reference for submit_bh */
2221                         get_bh(bh);
2222
2223                         set_buffer_uptodate(bh);
2224                         lock_buffer(bh);
2225                         bh->b_end_io = btrfs_end_buffer_write_sync;
2226                 }
2227
2228                 if (i == last_barrier && do_barriers && device->barriers) {
2229                         ret = submit_bh(WRITE_BARRIER, bh);
2230                         if (ret == -EOPNOTSUPP) {
2231                                 printk("btrfs: disabling barriers on dev %s\n",
2232                                        device->name);
2233                                 set_buffer_uptodate(bh);
2234                                 device->barriers = 0;
2235                                 /* one reference for submit_bh */
2236                                 get_bh(bh);
2237                                 lock_buffer(bh);
2238                                 ret = submit_bh(WRITE_SYNC, bh);
2239                         }
2240                 } else {
2241                         ret = submit_bh(WRITE_SYNC, bh);
2242                 }
2243
2244                 if (ret)
2245                         errors++;
2246         }
2247         return errors < i ? 0 : -1;
2248 }
2249
2250 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2251 {
2252         struct list_head *head;
2253         struct btrfs_device *dev;
2254         struct btrfs_super_block *sb;
2255         struct btrfs_dev_item *dev_item;
2256         int ret;
2257         int do_barriers;
2258         int max_errors;
2259         int total_errors = 0;
2260         u64 flags;
2261
2262         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
2263         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2264
2265         sb = &root->fs_info->super_for_commit;
2266         dev_item = &sb->dev_item;
2267
2268         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2269         head = &root->fs_info->fs_devices->devices;
2270         list_for_each_entry(dev, head, dev_list) {
2271                 if (!dev->bdev) {
2272                         total_errors++;
2273                         continue;
2274                 }
2275                 if (!dev->in_fs_metadata || !dev->writeable)
2276                         continue;
2277
2278                 btrfs_set_stack_device_generation(dev_item, 0);
2279                 btrfs_set_stack_device_type(dev_item, dev->type);
2280                 btrfs_set_stack_device_id(dev_item, dev->devid);
2281                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2282                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2283                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2284                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2285                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2286                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2287                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2288
2289                 flags = btrfs_super_flags(sb);
2290                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2291
2292                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2293                 if (ret)
2294                         total_errors++;
2295         }
2296         if (total_errors > max_errors) {
2297                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2298                        total_errors);
2299                 BUG();
2300         }
2301
2302         total_errors = 0;
2303         list_for_each_entry(dev, head, dev_list) {
2304                 if (!dev->bdev)
2305                         continue;
2306                 if (!dev->in_fs_metadata || !dev->writeable)
2307                         continue;
2308
2309                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2310                 if (ret)
2311                         total_errors++;
2312         }
2313         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2314         if (total_errors > max_errors) {
2315                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2316                        total_errors);
2317                 BUG();
2318         }
2319         return 0;
2320 }
2321
2322 int write_ctree_super(struct btrfs_trans_handle *trans,
2323                       struct btrfs_root *root, int max_mirrors)
2324 {
2325         int ret;
2326
2327         ret = write_all_supers(root, max_mirrors);
2328         return ret;
2329 }
2330
2331 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2332 {
2333         spin_lock(&fs_info->fs_roots_radix_lock);
2334         radix_tree_delete(&fs_info->fs_roots_radix,
2335                           (unsigned long)root->root_key.objectid);
2336         spin_unlock(&fs_info->fs_roots_radix_lock);
2337
2338         if (btrfs_root_refs(&root->root_item) == 0)
2339                 synchronize_srcu(&fs_info->subvol_srcu);
2340
2341         free_fs_root(root);
2342         return 0;
2343 }
2344
2345 static void free_fs_root(struct btrfs_root *root)
2346 {
2347         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2348         if (root->anon_super.s_dev) {
2349                 down_write(&root->anon_super.s_umount);
2350                 kill_anon_super(&root->anon_super);
2351         }
2352         free_extent_buffer(root->node);
2353         free_extent_buffer(root->commit_root);
2354         kfree(root->name);
2355         kfree(root);
2356 }
2357
2358 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2359 {
2360         int ret;
2361         struct btrfs_root *gang[8];
2362         int i;
2363
2364         while (!list_empty(&fs_info->dead_roots)) {
2365                 gang[0] = list_entry(fs_info->dead_roots.next,
2366                                      struct btrfs_root, root_list);
2367                 list_del(&gang[0]->root_list);
2368
2369                 if (gang[0]->in_radix) {
2370                         btrfs_free_fs_root(fs_info, gang[0]);
2371                 } else {
2372                         free_extent_buffer(gang[0]->node);
2373                         free_extent_buffer(gang[0]->commit_root);
2374                         kfree(gang[0]);
2375                 }
2376         }
2377
2378         while (1) {
2379                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2380                                              (void **)gang, 0,
2381                                              ARRAY_SIZE(gang));
2382                 if (!ret)
2383                         break;
2384                 for (i = 0; i < ret; i++)
2385                         btrfs_free_fs_root(fs_info, gang[i]);
2386         }
2387         return 0;
2388 }
2389
2390 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2391 {
2392         u64 root_objectid = 0;
2393         struct btrfs_root *gang[8];
2394         int i;
2395         int ret;
2396
2397         while (1) {
2398                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2399                                              (void **)gang, root_objectid,
2400                                              ARRAY_SIZE(gang));
2401                 if (!ret)
2402                         break;
2403
2404                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2405                 for (i = 0; i < ret; i++) {
2406                         root_objectid = gang[i]->root_key.objectid;
2407                         btrfs_orphan_cleanup(gang[i]);
2408                 }
2409                 root_objectid++;
2410         }
2411         return 0;
2412 }
2413
2414 int btrfs_commit_super(struct btrfs_root *root)
2415 {
2416         struct btrfs_trans_handle *trans;
2417         int ret;
2418
2419         mutex_lock(&root->fs_info->cleaner_mutex);
2420         btrfs_run_delayed_iputs(root);
2421         btrfs_clean_old_snapshots(root);
2422         mutex_unlock(&root->fs_info->cleaner_mutex);
2423
2424         /* wait until ongoing cleanup work done */
2425         down_write(&root->fs_info->cleanup_work_sem);
2426         up_write(&root->fs_info->cleanup_work_sem);
2427
2428         trans = btrfs_join_transaction(root, 1);
2429         ret = btrfs_commit_transaction(trans, root);
2430         BUG_ON(ret);
2431         /* run commit again to drop the original snapshot */
2432         trans = btrfs_join_transaction(root, 1);
2433         btrfs_commit_transaction(trans, root);
2434         ret = btrfs_write_and_wait_transaction(NULL, root);
2435         BUG_ON(ret);
2436
2437         ret = write_ctree_super(NULL, root, 0);
2438         return ret;
2439 }
2440
2441 int close_ctree(struct btrfs_root *root)
2442 {
2443         struct btrfs_fs_info *fs_info = root->fs_info;
2444         int ret;
2445
2446         fs_info->closing = 1;
2447         smp_mb();
2448
2449         btrfs_put_block_group_cache(fs_info);
2450         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
2451                 ret =  btrfs_commit_super(root);
2452                 if (ret)
2453                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
2454         }
2455
2456         kthread_stop(root->fs_info->transaction_kthread);
2457         kthread_stop(root->fs_info->cleaner_kthread);
2458
2459         fs_info->closing = 2;
2460         smp_mb();
2461
2462         if (fs_info->delalloc_bytes) {
2463                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
2464                        (unsigned long long)fs_info->delalloc_bytes);
2465         }
2466         if (fs_info->total_ref_cache_size) {
2467                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
2468                        (unsigned long long)fs_info->total_ref_cache_size);
2469         }
2470
2471         free_extent_buffer(fs_info->extent_root->node);
2472         free_extent_buffer(fs_info->extent_root->commit_root);
2473         free_extent_buffer(fs_info->tree_root->node);
2474         free_extent_buffer(fs_info->tree_root->commit_root);
2475         free_extent_buffer(root->fs_info->chunk_root->node);
2476         free_extent_buffer(root->fs_info->chunk_root->commit_root);
2477         free_extent_buffer(root->fs_info->dev_root->node);
2478         free_extent_buffer(root->fs_info->dev_root->commit_root);
2479         free_extent_buffer(root->fs_info->csum_root->node);
2480         free_extent_buffer(root->fs_info->csum_root->commit_root);
2481
2482         btrfs_free_block_groups(root->fs_info);
2483
2484         del_fs_roots(fs_info);
2485
2486         iput(fs_info->btree_inode);
2487
2488         btrfs_stop_workers(&fs_info->generic_worker);
2489         btrfs_stop_workers(&fs_info->fixup_workers);
2490         btrfs_stop_workers(&fs_info->delalloc_workers);
2491         btrfs_stop_workers(&fs_info->workers);
2492         btrfs_stop_workers(&fs_info->endio_workers);
2493         btrfs_stop_workers(&fs_info->endio_meta_workers);
2494         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2495         btrfs_stop_workers(&fs_info->endio_write_workers);
2496         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2497         btrfs_stop_workers(&fs_info->submit_workers);
2498
2499         btrfs_close_devices(fs_info->fs_devices);
2500         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2501
2502         bdi_destroy(&fs_info->bdi);
2503         cleanup_srcu_struct(&fs_info->subvol_srcu);
2504
2505         kfree(fs_info->extent_root);
2506         kfree(fs_info->tree_root);
2507         kfree(fs_info->chunk_root);
2508         kfree(fs_info->dev_root);
2509         kfree(fs_info->csum_root);
2510         return 0;
2511 }
2512
2513 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
2514 {
2515         int ret;
2516         struct inode *btree_inode = buf->first_page->mapping->host;
2517
2518         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
2519                                      NULL);
2520         if (!ret)
2521                 return ret;
2522
2523         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
2524                                     parent_transid);
2525         return !ret;
2526 }
2527
2528 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
2529 {
2530         struct inode *btree_inode = buf->first_page->mapping->host;
2531         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
2532                                           buf);
2533 }
2534
2535 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
2536 {
2537         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2538         u64 transid = btrfs_header_generation(buf);
2539         struct inode *btree_inode = root->fs_info->btree_inode;
2540         int was_dirty;
2541
2542         btrfs_assert_tree_locked(buf);
2543         if (transid != root->fs_info->generation) {
2544                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
2545                        "found %llu running %llu\n",
2546                         (unsigned long long)buf->start,
2547                         (unsigned long long)transid,
2548                         (unsigned long long)root->fs_info->generation);
2549                 WARN_ON(1);
2550         }
2551         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
2552                                             buf);
2553         if (!was_dirty) {
2554                 spin_lock(&root->fs_info->delalloc_lock);
2555                 root->fs_info->dirty_metadata_bytes += buf->len;
2556                 spin_unlock(&root->fs_info->delalloc_lock);
2557         }
2558 }
2559
2560 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
2561 {
2562         /*
2563          * looks as though older kernels can get into trouble with
2564          * this code, they end up stuck in balance_dirty_pages forever
2565          */
2566         u64 num_dirty;
2567         unsigned long thresh = 32 * 1024 * 1024;
2568
2569         if (current->flags & PF_MEMALLOC)
2570                 return;
2571
2572         num_dirty = root->fs_info->dirty_metadata_bytes;
2573
2574         if (num_dirty > thresh) {
2575                 balance_dirty_pages_ratelimited_nr(
2576                                    root->fs_info->btree_inode->i_mapping, 1);
2577         }
2578         return;
2579 }
2580
2581 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
2582 {
2583         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
2584         int ret;
2585         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
2586         if (ret == 0)
2587                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
2588         return ret;
2589 }
2590
2591 int btree_lock_page_hook(struct page *page)
2592 {
2593         struct inode *inode = page->mapping->host;
2594         struct btrfs_root *root = BTRFS_I(inode)->root;
2595         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
2596         struct extent_buffer *eb;
2597         unsigned long len;
2598         u64 bytenr = page_offset(page);
2599
2600         if (page->private == EXTENT_PAGE_PRIVATE)
2601                 goto out;
2602
2603         len = page->private >> 2;
2604         eb = find_extent_buffer(io_tree, bytenr, len, GFP_NOFS);
2605         if (!eb)
2606                 goto out;
2607
2608         btrfs_tree_lock(eb);
2609         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
2610
2611         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
2612                 spin_lock(&root->fs_info->delalloc_lock);
2613                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
2614                         root->fs_info->dirty_metadata_bytes -= eb->len;
2615                 else
2616                         WARN_ON(1);
2617                 spin_unlock(&root->fs_info->delalloc_lock);
2618         }
2619
2620         btrfs_tree_unlock(eb);
2621         free_extent_buffer(eb);
2622 out:
2623         lock_page(page);
2624         return 0;
2625 }
2626
2627 static struct extent_io_ops btree_extent_io_ops = {
2628         .write_cache_pages_lock_hook = btree_lock_page_hook,
2629         .readpage_end_io_hook = btree_readpage_end_io_hook,
2630         .submit_bio_hook = btree_submit_bio_hook,
2631         /* note we're sharing with inode.c for the merge bio hook */
2632         .merge_bio_hook = btrfs_merge_bio_hook,
2633 };