Btrfs: Index extent buffers in an rbtree
[sfrench/cifs-2.6.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/version.h>
20 #include <linux/fs.h>
21 #include <linux/blkdev.h>
22 #include <linux/scatterlist.h>
23 #include <linux/swap.h>
24 #include <linux/radix-tree.h>
25 #include <linux/writeback.h>
26 #include <linux/buffer_head.h> // for block_sync_page
27 #include <linux/workqueue.h>
28 #include <linux/kthread.h>
29 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,20)
30 # include <linux/freezer.h>
31 #else
32 # include <linux/sched.h>
33 #endif
34 #include "crc32c.h"
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "volumes.h"
40 #include "print-tree.h"
41 #include "async-thread.h"
42 #include "locking.h"
43
44 #if 0
45 static int check_tree_block(struct btrfs_root *root, struct extent_buffer *buf)
46 {
47         if (extent_buffer_blocknr(buf) != btrfs_header_blocknr(buf)) {
48                 printk(KERN_CRIT "buf blocknr(buf) is %llu, header is %llu\n",
49                        (unsigned long long)extent_buffer_blocknr(buf),
50                        (unsigned long long)btrfs_header_blocknr(buf));
51                 return 1;
52         }
53         return 0;
54 }
55 #endif
56
57 static struct extent_io_ops btree_extent_io_ops;
58 static void end_workqueue_fn(struct btrfs_work *work);
59
60 struct end_io_wq {
61         struct bio *bio;
62         bio_end_io_t *end_io;
63         void *private;
64         struct btrfs_fs_info *info;
65         int error;
66         int metadata;
67         struct list_head list;
68         struct btrfs_work work;
69 };
70
71 struct async_submit_bio {
72         struct inode *inode;
73         struct bio *bio;
74         struct list_head list;
75         extent_submit_bio_hook_t *submit_bio_hook;
76         int rw;
77         int mirror_num;
78         struct btrfs_work work;
79 };
80
81 struct extent_map *btree_get_extent(struct inode *inode, struct page *page,
82                                     size_t page_offset, u64 start, u64 len,
83                                     int create)
84 {
85         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
86         struct extent_map *em;
87         int ret;
88
89         spin_lock(&em_tree->lock);
90         em = lookup_extent_mapping(em_tree, start, len);
91         if (em) {
92                 em->bdev =
93                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
94                 spin_unlock(&em_tree->lock);
95                 goto out;
96         }
97         spin_unlock(&em_tree->lock);
98
99         em = alloc_extent_map(GFP_NOFS);
100         if (!em) {
101                 em = ERR_PTR(-ENOMEM);
102                 goto out;
103         }
104         em->start = 0;
105         em->len = (u64)-1;
106         em->block_start = 0;
107         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
108
109         spin_lock(&em_tree->lock);
110         ret = add_extent_mapping(em_tree, em);
111         if (ret == -EEXIST) {
112                 u64 failed_start = em->start;
113                 u64 failed_len = em->len;
114
115                 printk("failed to insert %Lu %Lu -> %Lu into tree\n",
116                        em->start, em->len, em->block_start);
117                 free_extent_map(em);
118                 em = lookup_extent_mapping(em_tree, start, len);
119                 if (em) {
120                         printk("after failing, found %Lu %Lu %Lu\n",
121                                em->start, em->len, em->block_start);
122                         ret = 0;
123                 } else {
124                         em = lookup_extent_mapping(em_tree, failed_start,
125                                                    failed_len);
126                         if (em) {
127                                 printk("double failure lookup gives us "
128                                        "%Lu %Lu -> %Lu\n", em->start,
129                                        em->len, em->block_start);
130                                 free_extent_map(em);
131                         }
132                         ret = -EIO;
133                 }
134         } else if (ret) {
135                 free_extent_map(em);
136                 em = NULL;
137         }
138         spin_unlock(&em_tree->lock);
139
140         if (ret)
141                 em = ERR_PTR(ret);
142 out:
143         return em;
144 }
145
146 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
147 {
148         return btrfs_crc32c(seed, data, len);
149 }
150
151 void btrfs_csum_final(u32 crc, char *result)
152 {
153         *(__le32 *)result = ~cpu_to_le32(crc);
154 }
155
156 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
157                            int verify)
158 {
159         char result[BTRFS_CRC32_SIZE];
160         unsigned long len;
161         unsigned long cur_len;
162         unsigned long offset = BTRFS_CSUM_SIZE;
163         char *map_token = NULL;
164         char *kaddr;
165         unsigned long map_start;
166         unsigned long map_len;
167         int err;
168         u32 crc = ~(u32)0;
169
170         len = buf->len - offset;
171         while(len > 0) {
172                 err = map_private_extent_buffer(buf, offset, 32,
173                                         &map_token, &kaddr,
174                                         &map_start, &map_len, KM_USER0);
175                 if (err) {
176                         printk("failed to map extent buffer! %lu\n",
177                                offset);
178                         return 1;
179                 }
180                 cur_len = min(len, map_len - (offset - map_start));
181                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
182                                       crc, cur_len);
183                 len -= cur_len;
184                 offset += cur_len;
185                 unmap_extent_buffer(buf, map_token, KM_USER0);
186         }
187         btrfs_csum_final(crc, result);
188
189         if (verify) {
190                 int from_this_trans = 0;
191
192                 if (root->fs_info->running_transaction &&
193                     btrfs_header_generation(buf) ==
194                     root->fs_info->running_transaction->transid)
195                         from_this_trans = 1;
196
197                 /* FIXME, this is not good */
198                 if (memcmp_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE)) {
199                         u32 val;
200                         u32 found = 0;
201                         memcpy(&found, result, BTRFS_CRC32_SIZE);
202
203                         read_extent_buffer(buf, &val, 0, BTRFS_CRC32_SIZE);
204                         printk("btrfs: %s checksum verify failed on %llu "
205                                "wanted %X found %X from_this_trans %d "
206                                "level %d\n",
207                                root->fs_info->sb->s_id,
208                                buf->start, val, found, from_this_trans,
209                                btrfs_header_level(buf));
210                         return 1;
211                 }
212         } else {
213                 write_extent_buffer(buf, result, 0, BTRFS_CRC32_SIZE);
214         }
215         return 0;
216 }
217
218 static int verify_parent_transid(struct extent_io_tree *io_tree,
219                                  struct extent_buffer *eb, u64 parent_transid)
220 {
221         int ret;
222
223         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
224                 return 0;
225
226         lock_extent(io_tree, eb->start, eb->start + eb->len - 1, GFP_NOFS);
227         if (extent_buffer_uptodate(io_tree, eb) &&
228             btrfs_header_generation(eb) == parent_transid) {
229                 ret = 0;
230                 goto out;
231         }
232         printk("parent transid verify failed on %llu wanted %llu found %llu\n",
233                (unsigned long long)eb->start,
234                (unsigned long long)parent_transid,
235                (unsigned long long)btrfs_header_generation(eb));
236         ret = 1;
237 out:
238         clear_extent_buffer_uptodate(io_tree, eb);
239         unlock_extent(io_tree, eb->start, eb->start + eb->len - 1,
240                       GFP_NOFS);
241         return ret;
242
243 }
244
245 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
246                                           struct extent_buffer *eb,
247                                           u64 start, u64 parent_transid)
248 {
249         struct extent_io_tree *io_tree;
250         int ret;
251         int num_copies = 0;
252         int mirror_num = 0;
253
254         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
255         while (1) {
256                 ret = read_extent_buffer_pages(io_tree, eb, start, 1,
257                                                btree_get_extent, mirror_num);
258                 if (!ret &&
259                     !verify_parent_transid(io_tree, eb, parent_transid))
260                         return ret;
261
262                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
263                                               eb->start, eb->len);
264                 if (num_copies == 1)
265                         return ret;
266
267                 mirror_num++;
268                 if (mirror_num > num_copies)
269                         return ret;
270         }
271         return -EIO;
272 }
273
274 int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
275 {
276         struct extent_io_tree *tree;
277         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
278         u64 found_start;
279         int found_level;
280         unsigned long len;
281         struct extent_buffer *eb;
282         int ret;
283
284         tree = &BTRFS_I(page->mapping->host)->io_tree;
285
286         if (page->private == EXTENT_PAGE_PRIVATE)
287                 goto out;
288         if (!page->private)
289                 goto out;
290         len = page->private >> 2;
291         if (len == 0) {
292                 WARN_ON(1);
293         }
294         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
295         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
296                                              btrfs_header_generation(eb));
297         BUG_ON(ret);
298         found_start = btrfs_header_bytenr(eb);
299         if (found_start != start) {
300                 printk("warning: eb start incorrect %Lu buffer %Lu len %lu\n",
301                        start, found_start, len);
302                 WARN_ON(1);
303                 goto err;
304         }
305         if (eb->first_page != page) {
306                 printk("bad first page %lu %lu\n", eb->first_page->index,
307                        page->index);
308                 WARN_ON(1);
309                 goto err;
310         }
311         if (!PageUptodate(page)) {
312                 printk("csum not up to date page %lu\n", page->index);
313                 WARN_ON(1);
314                 goto err;
315         }
316         found_level = btrfs_header_level(eb);
317         spin_lock(&root->fs_info->hash_lock);
318         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
319         spin_unlock(&root->fs_info->hash_lock);
320         csum_tree_block(root, eb, 0);
321 err:
322         free_extent_buffer(eb);
323 out:
324         return 0;
325 }
326
327 static int btree_writepage_io_hook(struct page *page, u64 start, u64 end)
328 {
329         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
330
331         csum_dirty_buffer(root, page);
332         return 0;
333 }
334
335 int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
336                                struct extent_state *state)
337 {
338         struct extent_io_tree *tree;
339         u64 found_start;
340         int found_level;
341         unsigned long len;
342         struct extent_buffer *eb;
343         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
344         int ret = 0;
345
346         tree = &BTRFS_I(page->mapping->host)->io_tree;
347         if (page->private == EXTENT_PAGE_PRIVATE)
348                 goto out;
349         if (!page->private)
350                 goto out;
351         len = page->private >> 2;
352         if (len == 0) {
353                 WARN_ON(1);
354         }
355         eb = alloc_extent_buffer(tree, start, len, page, GFP_NOFS);
356
357         found_start = btrfs_header_bytenr(eb);
358         if (found_start != start) {
359                 ret = -EIO;
360                 goto err;
361         }
362         if (eb->first_page != page) {
363                 printk("bad first page %lu %lu\n", eb->first_page->index,
364                        page->index);
365                 WARN_ON(1);
366                 ret = -EIO;
367                 goto err;
368         }
369         if (memcmp_extent_buffer(eb, root->fs_info->fsid,
370                                  (unsigned long)btrfs_header_fsid(eb),
371                                  BTRFS_FSID_SIZE)) {
372                 printk("bad fsid on block %Lu\n", eb->start);
373                 ret = -EIO;
374                 goto err;
375         }
376         found_level = btrfs_header_level(eb);
377
378         ret = csum_tree_block(root, eb, 1);
379         if (ret)
380                 ret = -EIO;
381
382         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
383         end = eb->start + end - 1;
384 err:
385         free_extent_buffer(eb);
386 out:
387         return ret;
388 }
389
390 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
391 static void end_workqueue_bio(struct bio *bio, int err)
392 #else
393 static int end_workqueue_bio(struct bio *bio,
394                                    unsigned int bytes_done, int err)
395 #endif
396 {
397         struct end_io_wq *end_io_wq = bio->bi_private;
398         struct btrfs_fs_info *fs_info;
399
400 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
401         if (bio->bi_size)
402                 return 1;
403 #endif
404
405         fs_info = end_io_wq->info;
406         end_io_wq->error = err;
407         end_io_wq->work.func = end_workqueue_fn;
408         end_io_wq->work.flags = 0;
409         if (bio->bi_rw & (1 << BIO_RW))
410                 btrfs_queue_worker(&fs_info->endio_write_workers,
411                                    &end_io_wq->work);
412         else
413                 btrfs_queue_worker(&fs_info->endio_workers, &end_io_wq->work);
414
415 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
416         return 0;
417 #endif
418 }
419
420 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
421                         int metadata)
422 {
423         struct end_io_wq *end_io_wq;
424         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
425         if (!end_io_wq)
426                 return -ENOMEM;
427
428         end_io_wq->private = bio->bi_private;
429         end_io_wq->end_io = bio->bi_end_io;
430         end_io_wq->info = info;
431         end_io_wq->error = 0;
432         end_io_wq->bio = bio;
433         end_io_wq->metadata = metadata;
434
435         bio->bi_private = end_io_wq;
436         bio->bi_end_io = end_workqueue_bio;
437         return 0;
438 }
439
440 static void run_one_async_submit(struct btrfs_work *work)
441 {
442         struct btrfs_fs_info *fs_info;
443         struct async_submit_bio *async;
444
445         async = container_of(work, struct  async_submit_bio, work);
446         fs_info = BTRFS_I(async->inode)->root->fs_info;
447         atomic_dec(&fs_info->nr_async_submits);
448         async->submit_bio_hook(async->inode, async->rw, async->bio,
449                                async->mirror_num);
450         kfree(async);
451 }
452
453 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
454                         int rw, struct bio *bio, int mirror_num,
455                         extent_submit_bio_hook_t *submit_bio_hook)
456 {
457         struct async_submit_bio *async;
458
459         async = kmalloc(sizeof(*async), GFP_NOFS);
460         if (!async)
461                 return -ENOMEM;
462
463         async->inode = inode;
464         async->rw = rw;
465         async->bio = bio;
466         async->mirror_num = mirror_num;
467         async->submit_bio_hook = submit_bio_hook;
468         async->work.func = run_one_async_submit;
469         async->work.flags = 0;
470         atomic_inc(&fs_info->nr_async_submits);
471         btrfs_queue_worker(&fs_info->workers, &async->work);
472         return 0;
473 }
474
475 static int __btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
476                                  int mirror_num)
477 {
478         struct btrfs_root *root = BTRFS_I(inode)->root;
479         u64 offset;
480         int ret;
481
482         offset = bio->bi_sector << 9;
483
484         /*
485          * when we're called for a write, we're already in the async
486          * submission context.  Just jump ingo btrfs_map_bio
487          */
488         if (rw & (1 << BIO_RW)) {
489                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
490                                      mirror_num, 0);
491         }
492
493         /*
494          * called for a read, do the setup so that checksum validation
495          * can happen in the async kernel threads
496          */
497         ret = btrfs_bio_wq_end_io(root->fs_info, bio, 1);
498         BUG_ON(ret);
499
500         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
501 }
502
503 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
504                                  int mirror_num)
505 {
506         /*
507          * kthread helpers are used to submit writes so that checksumming
508          * can happen in parallel across all CPUs
509          */
510         if (!(rw & (1 << BIO_RW))) {
511                 return __btree_submit_bio_hook(inode, rw, bio, mirror_num);
512         }
513         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
514                                    inode, rw, bio, mirror_num,
515                                    __btree_submit_bio_hook);
516 }
517
518 static int btree_writepage(struct page *page, struct writeback_control *wbc)
519 {
520         struct extent_io_tree *tree;
521         tree = &BTRFS_I(page->mapping->host)->io_tree;
522         return extent_write_full_page(tree, page, btree_get_extent, wbc);
523 }
524
525 static int btree_writepages(struct address_space *mapping,
526                             struct writeback_control *wbc)
527 {
528         struct extent_io_tree *tree;
529         tree = &BTRFS_I(mapping->host)->io_tree;
530         if (wbc->sync_mode == WB_SYNC_NONE) {
531                 u64 num_dirty;
532                 u64 start = 0;
533                 unsigned long thresh = 96 * 1024 * 1024;
534
535                 if (wbc->for_kupdate)
536                         return 0;
537
538                 if (current_is_pdflush()) {
539                         thresh = 96 * 1024 * 1024;
540                 } else {
541                         thresh = 8 * 1024 * 1024;
542                 }
543                 num_dirty = count_range_bits(tree, &start, (u64)-1,
544                                              thresh, EXTENT_DIRTY);
545                 if (num_dirty < thresh) {
546                         return 0;
547                 }
548         }
549         return extent_writepages(tree, mapping, btree_get_extent, wbc);
550 }
551
552 int btree_readpage(struct file *file, struct page *page)
553 {
554         struct extent_io_tree *tree;
555         tree = &BTRFS_I(page->mapping->host)->io_tree;
556         return extent_read_full_page(tree, page, btree_get_extent);
557 }
558
559 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
560 {
561         struct extent_io_tree *tree;
562         struct extent_map_tree *map;
563         int ret;
564
565         tree = &BTRFS_I(page->mapping->host)->io_tree;
566         map = &BTRFS_I(page->mapping->host)->extent_tree;
567
568         ret = try_release_extent_state(map, tree, page, gfp_flags);
569         if (!ret) {
570                 return 0;
571         }
572
573         ret = try_release_extent_buffer(tree, page);
574         if (ret == 1) {
575                 ClearPagePrivate(page);
576                 set_page_private(page, 0);
577                 page_cache_release(page);
578         }
579
580         return ret;
581 }
582
583 static void btree_invalidatepage(struct page *page, unsigned long offset)
584 {
585         struct extent_io_tree *tree;
586         tree = &BTRFS_I(page->mapping->host)->io_tree;
587         extent_invalidatepage(tree, page, offset);
588         btree_releasepage(page, GFP_NOFS);
589         if (PagePrivate(page)) {
590                 printk("warning page private not zero on page %Lu\n",
591                        page_offset(page));
592                 ClearPagePrivate(page);
593                 set_page_private(page, 0);
594                 page_cache_release(page);
595         }
596 }
597
598 #if 0
599 static int btree_writepage(struct page *page, struct writeback_control *wbc)
600 {
601         struct buffer_head *bh;
602         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
603         struct buffer_head *head;
604         if (!page_has_buffers(page)) {
605                 create_empty_buffers(page, root->fs_info->sb->s_blocksize,
606                                         (1 << BH_Dirty)|(1 << BH_Uptodate));
607         }
608         head = page_buffers(page);
609         bh = head;
610         do {
611                 if (buffer_dirty(bh))
612                         csum_tree_block(root, bh, 0);
613                 bh = bh->b_this_page;
614         } while (bh != head);
615         return block_write_full_page(page, btree_get_block, wbc);
616 }
617 #endif
618
619 static struct address_space_operations btree_aops = {
620         .readpage       = btree_readpage,
621         .writepage      = btree_writepage,
622         .writepages     = btree_writepages,
623         .releasepage    = btree_releasepage,
624         .invalidatepage = btree_invalidatepage,
625         .sync_page      = block_sync_page,
626 };
627
628 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
629                          u64 parent_transid)
630 {
631         struct extent_buffer *buf = NULL;
632         struct inode *btree_inode = root->fs_info->btree_inode;
633         int ret = 0;
634
635         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
636         if (!buf)
637                 return 0;
638         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
639                                  buf, 0, 0, btree_get_extent, 0);
640         free_extent_buffer(buf);
641         return ret;
642 }
643
644 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
645                                             u64 bytenr, u32 blocksize)
646 {
647         struct inode *btree_inode = root->fs_info->btree_inode;
648         struct extent_buffer *eb;
649         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
650                                 bytenr, blocksize, GFP_NOFS);
651         return eb;
652 }
653
654 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
655                                                  u64 bytenr, u32 blocksize)
656 {
657         struct inode *btree_inode = root->fs_info->btree_inode;
658         struct extent_buffer *eb;
659
660         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
661                                  bytenr, blocksize, NULL, GFP_NOFS);
662         return eb;
663 }
664
665
666 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
667                                       u32 blocksize, u64 parent_transid)
668 {
669         struct extent_buffer *buf = NULL;
670         struct inode *btree_inode = root->fs_info->btree_inode;
671         struct extent_io_tree *io_tree;
672         int ret;
673
674         io_tree = &BTRFS_I(btree_inode)->io_tree;
675
676         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
677         if (!buf)
678                 return NULL;
679
680         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
681
682         if (ret == 0) {
683                 buf->flags |= EXTENT_UPTODATE;
684         }
685         return buf;
686
687 }
688
689 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
690                      struct extent_buffer *buf)
691 {
692         struct inode *btree_inode = root->fs_info->btree_inode;
693         if (btrfs_header_generation(buf) ==
694             root->fs_info->running_transaction->transid) {
695                 WARN_ON(!btrfs_tree_locked(buf));
696                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
697                                           buf);
698         }
699         return 0;
700 }
701
702 int wait_on_tree_block_writeback(struct btrfs_root *root,
703                                  struct extent_buffer *buf)
704 {
705         struct inode *btree_inode = root->fs_info->btree_inode;
706         wait_on_extent_buffer_writeback(&BTRFS_I(btree_inode)->io_tree,
707                                         buf);
708         return 0;
709 }
710
711 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
712                         u32 stripesize, struct btrfs_root *root,
713                         struct btrfs_fs_info *fs_info,
714                         u64 objectid)
715 {
716         root->node = NULL;
717         root->inode = NULL;
718         root->commit_root = NULL;
719         root->sectorsize = sectorsize;
720         root->nodesize = nodesize;
721         root->leafsize = leafsize;
722         root->stripesize = stripesize;
723         root->ref_cows = 0;
724         root->track_dirty = 0;
725
726         root->fs_info = fs_info;
727         root->objectid = objectid;
728         root->last_trans = 0;
729         root->highest_inode = 0;
730         root->last_inode_alloc = 0;
731         root->name = NULL;
732         root->in_sysfs = 0;
733
734         INIT_LIST_HEAD(&root->dirty_list);
735         spin_lock_init(&root->node_lock);
736         mutex_init(&root->objectid_mutex);
737         memset(&root->root_key, 0, sizeof(root->root_key));
738         memset(&root->root_item, 0, sizeof(root->root_item));
739         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
740         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
741         root->defrag_trans_start = fs_info->generation;
742         init_completion(&root->kobj_unregister);
743         root->defrag_running = 0;
744         root->defrag_level = 0;
745         root->root_key.objectid = objectid;
746         return 0;
747 }
748
749 static int find_and_setup_root(struct btrfs_root *tree_root,
750                                struct btrfs_fs_info *fs_info,
751                                u64 objectid,
752                                struct btrfs_root *root)
753 {
754         int ret;
755         u32 blocksize;
756
757         __setup_root(tree_root->nodesize, tree_root->leafsize,
758                      tree_root->sectorsize, tree_root->stripesize,
759                      root, fs_info, objectid);
760         ret = btrfs_find_last_root(tree_root, objectid,
761                                    &root->root_item, &root->root_key);
762         BUG_ON(ret);
763
764         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
765         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
766                                      blocksize, 0);
767         BUG_ON(!root->node);
768         return 0;
769 }
770
771 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_fs_info *fs_info,
772                                                struct btrfs_key *location)
773 {
774         struct btrfs_root *root;
775         struct btrfs_root *tree_root = fs_info->tree_root;
776         struct btrfs_path *path;
777         struct extent_buffer *l;
778         u64 highest_inode;
779         u32 blocksize;
780         int ret = 0;
781
782         root = kzalloc(sizeof(*root), GFP_NOFS);
783         if (!root)
784                 return ERR_PTR(-ENOMEM);
785         if (location->offset == (u64)-1) {
786                 ret = find_and_setup_root(tree_root, fs_info,
787                                           location->objectid, root);
788                 if (ret) {
789                         kfree(root);
790                         return ERR_PTR(ret);
791                 }
792                 goto insert;
793         }
794
795         __setup_root(tree_root->nodesize, tree_root->leafsize,
796                      tree_root->sectorsize, tree_root->stripesize,
797                      root, fs_info, location->objectid);
798
799         path = btrfs_alloc_path();
800         BUG_ON(!path);
801         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
802         if (ret != 0) {
803                 if (ret > 0)
804                         ret = -ENOENT;
805                 goto out;
806         }
807         l = path->nodes[0];
808         read_extent_buffer(l, &root->root_item,
809                btrfs_item_ptr_offset(l, path->slots[0]),
810                sizeof(root->root_item));
811         memcpy(&root->root_key, location, sizeof(*location));
812         ret = 0;
813 out:
814         btrfs_release_path(root, path);
815         btrfs_free_path(path);
816         if (ret) {
817                 kfree(root);
818                 return ERR_PTR(ret);
819         }
820         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
821         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
822                                      blocksize, 0);
823         BUG_ON(!root->node);
824 insert:
825         root->ref_cows = 1;
826         ret = btrfs_find_highest_inode(root, &highest_inode);
827         if (ret == 0) {
828                 root->highest_inode = highest_inode;
829                 root->last_inode_alloc = highest_inode;
830         }
831         return root;
832 }
833
834 struct btrfs_root *btrfs_lookup_fs_root(struct btrfs_fs_info *fs_info,
835                                         u64 root_objectid)
836 {
837         struct btrfs_root *root;
838
839         if (root_objectid == BTRFS_ROOT_TREE_OBJECTID)
840                 return fs_info->tree_root;
841         if (root_objectid == BTRFS_EXTENT_TREE_OBJECTID)
842                 return fs_info->extent_root;
843
844         root = radix_tree_lookup(&fs_info->fs_roots_radix,
845                                  (unsigned long)root_objectid);
846         return root;
847 }
848
849 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
850                                               struct btrfs_key *location)
851 {
852         struct btrfs_root *root;
853         int ret;
854
855         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
856                 return fs_info->tree_root;
857         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
858                 return fs_info->extent_root;
859         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
860                 return fs_info->chunk_root;
861         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
862                 return fs_info->dev_root;
863
864         root = radix_tree_lookup(&fs_info->fs_roots_radix,
865                                  (unsigned long)location->objectid);
866         if (root)
867                 return root;
868
869         root = btrfs_read_fs_root_no_radix(fs_info, location);
870         if (IS_ERR(root))
871                 return root;
872         ret = radix_tree_insert(&fs_info->fs_roots_radix,
873                                 (unsigned long)root->root_key.objectid,
874                                 root);
875         if (ret) {
876                 free_extent_buffer(root->node);
877                 kfree(root);
878                 return ERR_PTR(ret);
879         }
880         ret = btrfs_find_dead_roots(fs_info->tree_root,
881                                     root->root_key.objectid, root);
882         BUG_ON(ret);
883
884         return root;
885 }
886
887 struct btrfs_root *btrfs_read_fs_root(struct btrfs_fs_info *fs_info,
888                                       struct btrfs_key *location,
889                                       const char *name, int namelen)
890 {
891         struct btrfs_root *root;
892         int ret;
893
894         root = btrfs_read_fs_root_no_name(fs_info, location);
895         if (!root)
896                 return NULL;
897
898         if (root->in_sysfs)
899                 return root;
900
901         ret = btrfs_set_root_name(root, name, namelen);
902         if (ret) {
903                 free_extent_buffer(root->node);
904                 kfree(root);
905                 return ERR_PTR(ret);
906         }
907
908         ret = btrfs_sysfs_add_root(root);
909         if (ret) {
910                 free_extent_buffer(root->node);
911                 kfree(root->name);
912                 kfree(root);
913                 return ERR_PTR(ret);
914         }
915         root->in_sysfs = 1;
916         return root;
917 }
918 #if 0
919 static int add_hasher(struct btrfs_fs_info *info, char *type) {
920         struct btrfs_hasher *hasher;
921
922         hasher = kmalloc(sizeof(*hasher), GFP_NOFS);
923         if (!hasher)
924                 return -ENOMEM;
925         hasher->hash_tfm = crypto_alloc_hash(type, 0, CRYPTO_ALG_ASYNC);
926         if (!hasher->hash_tfm) {
927                 kfree(hasher);
928                 return -EINVAL;
929         }
930         spin_lock(&info->hash_lock);
931         list_add(&hasher->list, &info->hashers);
932         spin_unlock(&info->hash_lock);
933         return 0;
934 }
935 #endif
936
937 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
938 {
939         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
940         int ret = 0;
941         int limit = 256 * info->fs_devices->open_devices;
942         struct list_head *cur;
943         struct btrfs_device *device;
944         struct backing_dev_info *bdi;
945
946         if ((bdi_bits & (1 << BDI_write_congested)) &&
947             atomic_read(&info->nr_async_submits) > limit) {
948                 return 1;
949         }
950
951         list_for_each(cur, &info->fs_devices->devices) {
952                 device = list_entry(cur, struct btrfs_device, dev_list);
953                 if (!device->bdev)
954                         continue;
955                 bdi = blk_get_backing_dev_info(device->bdev);
956                 if (bdi && bdi_congested(bdi, bdi_bits)) {
957                         ret = 1;
958                         break;
959                 }
960         }
961         return ret;
962 }
963
964 /*
965  * this unplugs every device on the box, and it is only used when page
966  * is null
967  */
968 static void __unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
969 {
970         struct list_head *cur;
971         struct btrfs_device *device;
972         struct btrfs_fs_info *info;
973
974         info = (struct btrfs_fs_info *)bdi->unplug_io_data;
975         list_for_each(cur, &info->fs_devices->devices) {
976                 device = list_entry(cur, struct btrfs_device, dev_list);
977                 bdi = blk_get_backing_dev_info(device->bdev);
978                 if (bdi->unplug_io_fn) {
979                         bdi->unplug_io_fn(bdi, page);
980                 }
981         }
982 }
983
984 void btrfs_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
985 {
986         struct inode *inode;
987         struct extent_map_tree *em_tree;
988         struct extent_map *em;
989         struct address_space *mapping;
990         u64 offset;
991
992         /* the generic O_DIRECT read code does this */
993         if (!page) {
994                 __unplug_io_fn(bdi, page);
995                 return;
996         }
997
998         /*
999          * page->mapping may change at any time.  Get a consistent copy
1000          * and use that for everything below
1001          */
1002         smp_mb();
1003         mapping = page->mapping;
1004         if (!mapping)
1005                 return;
1006
1007         inode = mapping->host;
1008         offset = page_offset(page);
1009
1010         em_tree = &BTRFS_I(inode)->extent_tree;
1011         spin_lock(&em_tree->lock);
1012         em = lookup_extent_mapping(em_tree, offset, PAGE_CACHE_SIZE);
1013         spin_unlock(&em_tree->lock);
1014         if (!em)
1015                 return;
1016
1017         offset = offset - em->start;
1018         btrfs_unplug_page(&BTRFS_I(inode)->root->fs_info->mapping_tree,
1019                           em->block_start + offset, page);
1020         free_extent_map(em);
1021 }
1022
1023 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1024 {
1025 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1026         bdi_init(bdi);
1027 #endif
1028         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1029         bdi->state              = 0;
1030         bdi->capabilities       = default_backing_dev_info.capabilities;
1031         bdi->unplug_io_fn       = btrfs_unplug_io_fn;
1032         bdi->unplug_io_data     = info;
1033         bdi->congested_fn       = btrfs_congested_fn;
1034         bdi->congested_data     = info;
1035         return 0;
1036 }
1037
1038 static int bio_ready_for_csum(struct bio *bio)
1039 {
1040         u64 length = 0;
1041         u64 buf_len = 0;
1042         u64 start = 0;
1043         struct page *page;
1044         struct extent_io_tree *io_tree = NULL;
1045         struct btrfs_fs_info *info = NULL;
1046         struct bio_vec *bvec;
1047         int i;
1048         int ret;
1049
1050         bio_for_each_segment(bvec, bio, i) {
1051                 page = bvec->bv_page;
1052                 if (page->private == EXTENT_PAGE_PRIVATE) {
1053                         length += bvec->bv_len;
1054                         continue;
1055                 }
1056                 if (!page->private) {
1057                         length += bvec->bv_len;
1058                         continue;
1059                 }
1060                 length = bvec->bv_len;
1061                 buf_len = page->private >> 2;
1062                 start = page_offset(page) + bvec->bv_offset;
1063                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1064                 info = BTRFS_I(page->mapping->host)->root->fs_info;
1065         }
1066         /* are we fully contained in this bio? */
1067         if (buf_len <= length)
1068                 return 1;
1069
1070         ret = extent_range_uptodate(io_tree, start + length,
1071                                     start + buf_len - 1);
1072         if (ret == 1)
1073                 return ret;
1074         return ret;
1075 }
1076
1077 /*
1078  * called by the kthread helper functions to finally call the bio end_io
1079  * functions.  This is where read checksum verification actually happens
1080  */
1081 static void end_workqueue_fn(struct btrfs_work *work)
1082 {
1083         struct bio *bio;
1084         struct end_io_wq *end_io_wq;
1085         struct btrfs_fs_info *fs_info;
1086         int error;
1087
1088         end_io_wq = container_of(work, struct end_io_wq, work);
1089         bio = end_io_wq->bio;
1090         fs_info = end_io_wq->info;
1091
1092         /* metadata bios are special because the whole tree block must
1093          * be checksummed at once.  This makes sure the entire block is in
1094          * ram and up to date before trying to verify things.  For
1095          * blocksize <= pagesize, it is basically a noop
1096          */
1097         if (end_io_wq->metadata && !bio_ready_for_csum(bio)) {
1098                 btrfs_queue_worker(&fs_info->endio_workers,
1099                                    &end_io_wq->work);
1100                 return;
1101         }
1102         error = end_io_wq->error;
1103         bio->bi_private = end_io_wq->private;
1104         bio->bi_end_io = end_io_wq->end_io;
1105         kfree(end_io_wq);
1106 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,23)
1107         bio_endio(bio, bio->bi_size, error);
1108 #else
1109         bio_endio(bio, error);
1110 #endif
1111 }
1112
1113 static int cleaner_kthread(void *arg)
1114 {
1115         struct btrfs_root *root = arg;
1116
1117         do {
1118                 smp_mb();
1119                 if (root->fs_info->closing)
1120                         break;
1121
1122                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1123                 mutex_lock(&root->fs_info->cleaner_mutex);
1124                 btrfs_clean_old_snapshots(root);
1125                 mutex_unlock(&root->fs_info->cleaner_mutex);
1126
1127                 if (freezing(current)) {
1128                         refrigerator();
1129                 } else {
1130                         smp_mb();
1131                         if (root->fs_info->closing)
1132                                 break;
1133                         set_current_state(TASK_INTERRUPTIBLE);
1134                         schedule();
1135                         __set_current_state(TASK_RUNNING);
1136                 }
1137         } while (!kthread_should_stop());
1138         return 0;
1139 }
1140
1141 static int transaction_kthread(void *arg)
1142 {
1143         struct btrfs_root *root = arg;
1144         struct btrfs_trans_handle *trans;
1145         struct btrfs_transaction *cur;
1146         unsigned long now;
1147         unsigned long delay;
1148         int ret;
1149
1150         do {
1151                 smp_mb();
1152                 if (root->fs_info->closing)
1153                         break;
1154
1155                 delay = HZ * 30;
1156                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1157                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1158
1159                 mutex_lock(&root->fs_info->trans_mutex);
1160                 cur = root->fs_info->running_transaction;
1161                 if (!cur) {
1162                         mutex_unlock(&root->fs_info->trans_mutex);
1163                         goto sleep;
1164                 }
1165                 now = get_seconds();
1166                 if (now < cur->start_time || now - cur->start_time < 30) {
1167                         mutex_unlock(&root->fs_info->trans_mutex);
1168                         delay = HZ * 5;
1169                         goto sleep;
1170                 }
1171                 mutex_unlock(&root->fs_info->trans_mutex);
1172                 trans = btrfs_start_transaction(root, 1);
1173                 ret = btrfs_commit_transaction(trans, root);
1174 sleep:
1175                 wake_up_process(root->fs_info->cleaner_kthread);
1176                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1177
1178                 if (freezing(current)) {
1179                         refrigerator();
1180                 } else {
1181                         if (root->fs_info->closing)
1182                                 break;
1183                         set_current_state(TASK_INTERRUPTIBLE);
1184                         schedule_timeout(delay);
1185                         __set_current_state(TASK_RUNNING);
1186                 }
1187         } while (!kthread_should_stop());
1188         return 0;
1189 }
1190
1191 struct btrfs_root *open_ctree(struct super_block *sb,
1192                               struct btrfs_fs_devices *fs_devices,
1193                               char *options)
1194 {
1195         u32 sectorsize;
1196         u32 nodesize;
1197         u32 leafsize;
1198         u32 blocksize;
1199         u32 stripesize;
1200         struct buffer_head *bh;
1201         struct btrfs_root *extent_root = kmalloc(sizeof(struct btrfs_root),
1202                                                  GFP_NOFS);
1203         struct btrfs_root *tree_root = kmalloc(sizeof(struct btrfs_root),
1204                                                GFP_NOFS);
1205         struct btrfs_fs_info *fs_info = kzalloc(sizeof(*fs_info),
1206                                                 GFP_NOFS);
1207         struct btrfs_root *chunk_root = kmalloc(sizeof(struct btrfs_root),
1208                                                 GFP_NOFS);
1209         struct btrfs_root *dev_root = kmalloc(sizeof(struct btrfs_root),
1210                                               GFP_NOFS);
1211         int ret;
1212         int err = -EINVAL;
1213
1214         struct btrfs_super_block *disk_super;
1215
1216         if (!extent_root || !tree_root || !fs_info) {
1217                 err = -ENOMEM;
1218                 goto fail;
1219         }
1220         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_NOFS);
1221         INIT_LIST_HEAD(&fs_info->trans_list);
1222         INIT_LIST_HEAD(&fs_info->dead_roots);
1223         INIT_LIST_HEAD(&fs_info->hashers);
1224         spin_lock_init(&fs_info->hash_lock);
1225         spin_lock_init(&fs_info->delalloc_lock);
1226         spin_lock_init(&fs_info->new_trans_lock);
1227
1228         init_completion(&fs_info->kobj_unregister);
1229         fs_info->tree_root = tree_root;
1230         fs_info->extent_root = extent_root;
1231         fs_info->chunk_root = chunk_root;
1232         fs_info->dev_root = dev_root;
1233         fs_info->fs_devices = fs_devices;
1234         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1235         INIT_LIST_HEAD(&fs_info->space_info);
1236         btrfs_mapping_init(&fs_info->mapping_tree);
1237         atomic_set(&fs_info->nr_async_submits, 0);
1238         atomic_set(&fs_info->throttles, 0);
1239         fs_info->sb = sb;
1240         fs_info->max_extent = (u64)-1;
1241         fs_info->max_inline = 8192 * 1024;
1242         setup_bdi(fs_info, &fs_info->bdi);
1243         fs_info->btree_inode = new_inode(sb);
1244         fs_info->btree_inode->i_ino = 1;
1245         fs_info->btree_inode->i_nlink = 1;
1246         fs_info->thread_pool_size = min(num_online_cpus() + 2, 8);
1247
1248         sb->s_blocksize = 4096;
1249         sb->s_blocksize_bits = blksize_bits(4096);
1250
1251         /*
1252          * we set the i_size on the btree inode to the max possible int.
1253          * the real end of the address space is determined by all of
1254          * the devices in the system
1255          */
1256         fs_info->btree_inode->i_size = OFFSET_MAX;
1257         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
1258         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
1259
1260         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
1261                              fs_info->btree_inode->i_mapping,
1262                              GFP_NOFS);
1263         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree,
1264                              GFP_NOFS);
1265
1266         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
1267
1268         extent_io_tree_init(&fs_info->free_space_cache,
1269                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1270         extent_io_tree_init(&fs_info->block_group_cache,
1271                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1272         extent_io_tree_init(&fs_info->pinned_extents,
1273                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1274         extent_io_tree_init(&fs_info->pending_del,
1275                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1276         extent_io_tree_init(&fs_info->extent_ins,
1277                              fs_info->btree_inode->i_mapping, GFP_NOFS);
1278         fs_info->do_barriers = 1;
1279
1280         BTRFS_I(fs_info->btree_inode)->root = tree_root;
1281         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
1282                sizeof(struct btrfs_key));
1283         insert_inode_hash(fs_info->btree_inode);
1284         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1285
1286         mutex_init(&fs_info->trans_mutex);
1287         mutex_init(&fs_info->drop_mutex);
1288         mutex_init(&fs_info->alloc_mutex);
1289         mutex_init(&fs_info->chunk_mutex);
1290         mutex_init(&fs_info->transaction_kthread_mutex);
1291         mutex_init(&fs_info->cleaner_mutex);
1292         mutex_init(&fs_info->volume_mutex);
1293         init_waitqueue_head(&fs_info->transaction_throttle);
1294         init_waitqueue_head(&fs_info->transaction_wait);
1295
1296 #if 0
1297         ret = add_hasher(fs_info, "crc32c");
1298         if (ret) {
1299                 printk("btrfs: failed hash setup, modprobe cryptomgr?\n");
1300                 err = -ENOMEM;
1301                 goto fail_iput;
1302         }
1303 #endif
1304         __setup_root(4096, 4096, 4096, 4096, tree_root,
1305                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
1306
1307
1308         bh = __bread(fs_devices->latest_bdev,
1309                      BTRFS_SUPER_INFO_OFFSET / 4096, 4096);
1310         if (!bh)
1311                 goto fail_iput;
1312
1313         memcpy(&fs_info->super_copy, bh->b_data, sizeof(fs_info->super_copy));
1314         brelse(bh);
1315
1316         memcpy(fs_info->fsid, fs_info->super_copy.fsid, BTRFS_FSID_SIZE);
1317
1318         disk_super = &fs_info->super_copy;
1319         if (!btrfs_super_root(disk_super))
1320                 goto fail_sb_buffer;
1321
1322         err = btrfs_parse_options(tree_root, options);
1323         if (err)
1324                 goto fail_sb_buffer;
1325
1326         /*
1327          * we need to start all the end_io workers up front because the
1328          * queue work function gets called at interrupt time, and so it
1329          * cannot dynamically grow.
1330          */
1331         btrfs_init_workers(&fs_info->workers, fs_info->thread_pool_size);
1332         btrfs_init_workers(&fs_info->submit_workers, fs_info->thread_pool_size);
1333         btrfs_init_workers(&fs_info->fixup_workers, 1);
1334         btrfs_init_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1335         btrfs_init_workers(&fs_info->endio_write_workers,
1336                            fs_info->thread_pool_size);
1337         btrfs_start_workers(&fs_info->workers, 1);
1338         btrfs_start_workers(&fs_info->submit_workers, 1);
1339         btrfs_start_workers(&fs_info->fixup_workers, 1);
1340         btrfs_start_workers(&fs_info->endio_workers, fs_info->thread_pool_size);
1341         btrfs_start_workers(&fs_info->endio_write_workers,
1342                             fs_info->thread_pool_size);
1343
1344         err = -EINVAL;
1345         if (btrfs_super_num_devices(disk_super) > fs_devices->open_devices) {
1346                 printk("Btrfs: wanted %llu devices, but found %llu\n",
1347                        (unsigned long long)btrfs_super_num_devices(disk_super),
1348                        (unsigned long long)fs_devices->open_devices);
1349                 if (btrfs_test_opt(tree_root, DEGRADED))
1350                         printk("continuing in degraded mode\n");
1351                 else {
1352                         goto fail_sb_buffer;
1353                 }
1354         }
1355
1356         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
1357
1358         nodesize = btrfs_super_nodesize(disk_super);
1359         leafsize = btrfs_super_leafsize(disk_super);
1360         sectorsize = btrfs_super_sectorsize(disk_super);
1361         stripesize = btrfs_super_stripesize(disk_super);
1362         tree_root->nodesize = nodesize;
1363         tree_root->leafsize = leafsize;
1364         tree_root->sectorsize = sectorsize;
1365         tree_root->stripesize = stripesize;
1366
1367         sb->s_blocksize = sectorsize;
1368         sb->s_blocksize_bits = blksize_bits(sectorsize);
1369
1370         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
1371                     sizeof(disk_super->magic))) {
1372                 printk("btrfs: valid FS not found on %s\n", sb->s_id);
1373                 goto fail_sb_buffer;
1374         }
1375
1376         mutex_lock(&fs_info->chunk_mutex);
1377         ret = btrfs_read_sys_array(tree_root);
1378         mutex_unlock(&fs_info->chunk_mutex);
1379         if (ret) {
1380                 printk("btrfs: failed to read the system array on %s\n",
1381                        sb->s_id);
1382                 goto fail_sys_array;
1383         }
1384
1385         blocksize = btrfs_level_size(tree_root,
1386                                      btrfs_super_chunk_root_level(disk_super));
1387
1388         __setup_root(nodesize, leafsize, sectorsize, stripesize,
1389                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
1390
1391         chunk_root->node = read_tree_block(chunk_root,
1392                                            btrfs_super_chunk_root(disk_super),
1393                                            blocksize, 0);
1394         BUG_ON(!chunk_root->node);
1395
1396         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
1397                  (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
1398                  BTRFS_UUID_SIZE);
1399
1400         mutex_lock(&fs_info->chunk_mutex);
1401         ret = btrfs_read_chunk_tree(chunk_root);
1402         mutex_unlock(&fs_info->chunk_mutex);
1403         BUG_ON(ret);
1404
1405         btrfs_close_extra_devices(fs_devices);
1406
1407         blocksize = btrfs_level_size(tree_root,
1408                                      btrfs_super_root_level(disk_super));
1409
1410
1411         tree_root->node = read_tree_block(tree_root,
1412                                           btrfs_super_root(disk_super),
1413                                           blocksize, 0);
1414         if (!tree_root->node)
1415                 goto fail_sb_buffer;
1416
1417
1418         ret = find_and_setup_root(tree_root, fs_info,
1419                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
1420         if (ret)
1421                 goto fail_tree_root;
1422         extent_root->track_dirty = 1;
1423
1424         ret = find_and_setup_root(tree_root, fs_info,
1425                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
1426         dev_root->track_dirty = 1;
1427
1428         if (ret)
1429                 goto fail_extent_root;
1430
1431         btrfs_read_block_groups(extent_root);
1432
1433         fs_info->generation = btrfs_super_generation(disk_super) + 1;
1434         fs_info->data_alloc_profile = (u64)-1;
1435         fs_info->metadata_alloc_profile = (u64)-1;
1436         fs_info->system_alloc_profile = fs_info->metadata_alloc_profile;
1437         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
1438                                                "btrfs-cleaner");
1439         if (!fs_info->cleaner_kthread)
1440                 goto fail_extent_root;
1441
1442         fs_info->transaction_kthread = kthread_run(transaction_kthread,
1443                                                    tree_root,
1444                                                    "btrfs-transaction");
1445         if (!fs_info->transaction_kthread)
1446                 goto fail_cleaner;
1447
1448
1449         return tree_root;
1450
1451 fail_cleaner:
1452         kthread_stop(fs_info->cleaner_kthread);
1453 fail_extent_root:
1454         free_extent_buffer(extent_root->node);
1455 fail_tree_root:
1456         free_extent_buffer(tree_root->node);
1457 fail_sys_array:
1458 fail_sb_buffer:
1459         btrfs_stop_workers(&fs_info->fixup_workers);
1460         btrfs_stop_workers(&fs_info->workers);
1461         btrfs_stop_workers(&fs_info->endio_workers);
1462         btrfs_stop_workers(&fs_info->endio_write_workers);
1463         btrfs_stop_workers(&fs_info->submit_workers);
1464 fail_iput:
1465         iput(fs_info->btree_inode);
1466 fail:
1467         btrfs_close_devices(fs_info->fs_devices);
1468         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1469
1470         kfree(extent_root);
1471         kfree(tree_root);
1472 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1473         bdi_destroy(&fs_info->bdi);
1474 #endif
1475         kfree(fs_info);
1476         return ERR_PTR(err);
1477 }
1478
1479 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
1480 {
1481         char b[BDEVNAME_SIZE];
1482
1483         if (uptodate) {
1484                 set_buffer_uptodate(bh);
1485         } else {
1486                 if (!buffer_eopnotsupp(bh) && printk_ratelimit()) {
1487                         printk(KERN_WARNING "lost page write due to "
1488                                         "I/O error on %s\n",
1489                                        bdevname(bh->b_bdev, b));
1490                 }
1491                 /* note, we dont' set_buffer_write_io_error because we have
1492                  * our own ways of dealing with the IO errors
1493                  */
1494                 clear_buffer_uptodate(bh);
1495         }
1496         unlock_buffer(bh);
1497         put_bh(bh);
1498 }
1499
1500 int write_all_supers(struct btrfs_root *root)
1501 {
1502         struct list_head *cur;
1503         struct list_head *head = &root->fs_info->fs_devices->devices;
1504         struct btrfs_device *dev;
1505         struct btrfs_super_block *sb;
1506         struct btrfs_dev_item *dev_item;
1507         struct buffer_head *bh;
1508         int ret;
1509         int do_barriers;
1510         int max_errors;
1511         int total_errors = 0;
1512         u32 crc;
1513         u64 flags;
1514
1515         max_errors = btrfs_super_num_devices(&root->fs_info->super_copy) - 1;
1516         do_barriers = !btrfs_test_opt(root, NOBARRIER);
1517
1518         sb = &root->fs_info->super_for_commit;
1519         dev_item = &sb->dev_item;
1520         list_for_each(cur, head) {
1521                 dev = list_entry(cur, struct btrfs_device, dev_list);
1522                 if (!dev->bdev) {
1523                         total_errors++;
1524                         continue;
1525                 }
1526                 if (!dev->in_fs_metadata)
1527                         continue;
1528
1529                 btrfs_set_stack_device_type(dev_item, dev->type);
1530                 btrfs_set_stack_device_id(dev_item, dev->devid);
1531                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
1532                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
1533                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
1534                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
1535                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
1536                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
1537                 flags = btrfs_super_flags(sb);
1538                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
1539
1540
1541                 crc = ~(u32)0;
1542                 crc = btrfs_csum_data(root, (char *)sb + BTRFS_CSUM_SIZE, crc,
1543                                       BTRFS_SUPER_INFO_SIZE - BTRFS_CSUM_SIZE);
1544                 btrfs_csum_final(crc, sb->csum);
1545
1546                 bh = __getblk(dev->bdev, BTRFS_SUPER_INFO_OFFSET / 4096,
1547                               BTRFS_SUPER_INFO_SIZE);
1548
1549                 memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
1550                 dev->pending_io = bh;
1551
1552                 get_bh(bh);
1553                 set_buffer_uptodate(bh);
1554                 lock_buffer(bh);
1555                 bh->b_end_io = btrfs_end_buffer_write_sync;
1556
1557                 if (do_barriers && dev->barriers) {
1558                         ret = submit_bh(WRITE_BARRIER, bh);
1559                         if (ret == -EOPNOTSUPP) {
1560                                 printk("btrfs: disabling barriers on dev %s\n",
1561                                        dev->name);
1562                                 set_buffer_uptodate(bh);
1563                                 dev->barriers = 0;
1564                                 get_bh(bh);
1565                                 lock_buffer(bh);
1566                                 ret = submit_bh(WRITE, bh);
1567                         }
1568                 } else {
1569                         ret = submit_bh(WRITE, bh);
1570                 }
1571                 if (ret)
1572                         total_errors++;
1573         }
1574         if (total_errors > max_errors) {
1575                 printk("btrfs: %d errors while writing supers\n", total_errors);
1576                 BUG();
1577         }
1578         total_errors = 0;
1579
1580         list_for_each(cur, head) {
1581                 dev = list_entry(cur, struct btrfs_device, dev_list);
1582                 if (!dev->bdev)
1583                         continue;
1584                 if (!dev->in_fs_metadata)
1585                         continue;
1586
1587                 BUG_ON(!dev->pending_io);
1588                 bh = dev->pending_io;
1589                 wait_on_buffer(bh);
1590                 if (!buffer_uptodate(dev->pending_io)) {
1591                         if (do_barriers && dev->barriers) {
1592                                 printk("btrfs: disabling barriers on dev %s\n",
1593                                        dev->name);
1594                                 set_buffer_uptodate(bh);
1595                                 get_bh(bh);
1596                                 lock_buffer(bh);
1597                                 dev->barriers = 0;
1598                                 ret = submit_bh(WRITE, bh);
1599                                 BUG_ON(ret);
1600                                 wait_on_buffer(bh);
1601                                 if (!buffer_uptodate(bh))
1602                                         total_errors++;
1603                         } else {
1604                                 total_errors++;
1605                         }
1606
1607                 }
1608                 dev->pending_io = NULL;
1609                 brelse(bh);
1610         }
1611         if (total_errors > max_errors) {
1612                 printk("btrfs: %d errors while writing supers\n", total_errors);
1613                 BUG();
1614         }
1615         return 0;
1616 }
1617
1618 int write_ctree_super(struct btrfs_trans_handle *trans, struct btrfs_root
1619                       *root)
1620 {
1621         int ret;
1622
1623         ret = write_all_supers(root);
1624         return ret;
1625 }
1626
1627 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
1628 {
1629         radix_tree_delete(&fs_info->fs_roots_radix,
1630                           (unsigned long)root->root_key.objectid);
1631         if (root->in_sysfs)
1632                 btrfs_sysfs_del_root(root);
1633         if (root->inode)
1634                 iput(root->inode);
1635         if (root->node)
1636                 free_extent_buffer(root->node);
1637         if (root->commit_root)
1638                 free_extent_buffer(root->commit_root);
1639         if (root->name)
1640                 kfree(root->name);
1641         kfree(root);
1642         return 0;
1643 }
1644
1645 static int del_fs_roots(struct btrfs_fs_info *fs_info)
1646 {
1647         int ret;
1648         struct btrfs_root *gang[8];
1649         int i;
1650
1651         while(1) {
1652                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
1653                                              (void **)gang, 0,
1654                                              ARRAY_SIZE(gang));
1655                 if (!ret)
1656                         break;
1657                 for (i = 0; i < ret; i++)
1658                         btrfs_free_fs_root(fs_info, gang[i]);
1659         }
1660         return 0;
1661 }
1662
1663 int close_ctree(struct btrfs_root *root)
1664 {
1665         int ret;
1666         struct btrfs_trans_handle *trans;
1667         struct btrfs_fs_info *fs_info = root->fs_info;
1668
1669         fs_info->closing = 1;
1670         smp_mb();
1671
1672         kthread_stop(root->fs_info->transaction_kthread);
1673         kthread_stop(root->fs_info->cleaner_kthread);
1674
1675         btrfs_clean_old_snapshots(root);
1676         trans = btrfs_start_transaction(root, 1);
1677         ret = btrfs_commit_transaction(trans, root);
1678         /* run commit again to  drop the original snapshot */
1679         trans = btrfs_start_transaction(root, 1);
1680         btrfs_commit_transaction(trans, root);
1681         ret = btrfs_write_and_wait_transaction(NULL, root);
1682         BUG_ON(ret);
1683
1684         write_ctree_super(NULL, root);
1685
1686         if (fs_info->delalloc_bytes) {
1687                 printk("btrfs: at unmount delalloc count %Lu\n",
1688                        fs_info->delalloc_bytes);
1689         }
1690         if (fs_info->extent_root->node)
1691                 free_extent_buffer(fs_info->extent_root->node);
1692
1693         if (fs_info->tree_root->node)
1694                 free_extent_buffer(fs_info->tree_root->node);
1695
1696         if (root->fs_info->chunk_root->node);
1697                 free_extent_buffer(root->fs_info->chunk_root->node);
1698
1699         if (root->fs_info->dev_root->node);
1700                 free_extent_buffer(root->fs_info->dev_root->node);
1701
1702         btrfs_free_block_groups(root->fs_info);
1703         del_fs_roots(fs_info);
1704
1705         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
1706
1707         truncate_inode_pages(fs_info->btree_inode->i_mapping, 0);
1708
1709         btrfs_stop_workers(&fs_info->fixup_workers);
1710         btrfs_stop_workers(&fs_info->workers);
1711         btrfs_stop_workers(&fs_info->endio_workers);
1712         btrfs_stop_workers(&fs_info->endio_write_workers);
1713         btrfs_stop_workers(&fs_info->submit_workers);
1714
1715         iput(fs_info->btree_inode);
1716 #if 0
1717         while(!list_empty(&fs_info->hashers)) {
1718                 struct btrfs_hasher *hasher;
1719                 hasher = list_entry(fs_info->hashers.next, struct btrfs_hasher,
1720                                     hashers);
1721                 list_del(&hasher->hashers);
1722                 crypto_free_hash(&fs_info->hash_tfm);
1723                 kfree(hasher);
1724         }
1725 #endif
1726         btrfs_close_devices(fs_info->fs_devices);
1727         btrfs_mapping_tree_free(&fs_info->mapping_tree);
1728
1729 #if LINUX_VERSION_CODE > KERNEL_VERSION(2,6,23)
1730         bdi_destroy(&fs_info->bdi);
1731 #endif
1732
1733         kfree(fs_info->extent_root);
1734         kfree(fs_info->tree_root);
1735         kfree(fs_info->chunk_root);
1736         kfree(fs_info->dev_root);
1737         return 0;
1738 }
1739
1740 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
1741 {
1742         int ret;
1743         struct inode *btree_inode = buf->first_page->mapping->host;
1744
1745         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf);
1746         if (!ret)
1747                 return ret;
1748
1749         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
1750                                     parent_transid);
1751         return !ret;
1752 }
1753
1754 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
1755 {
1756         struct inode *btree_inode = buf->first_page->mapping->host;
1757         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
1758                                           buf);
1759 }
1760
1761 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
1762 {
1763         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1764         u64 transid = btrfs_header_generation(buf);
1765         struct inode *btree_inode = root->fs_info->btree_inode;
1766
1767         WARN_ON(!btrfs_tree_locked(buf));
1768         if (transid != root->fs_info->generation) {
1769                 printk(KERN_CRIT "transid mismatch buffer %llu, found %Lu running %Lu\n",
1770                         (unsigned long long)buf->start,
1771                         transid, root->fs_info->generation);
1772                 WARN_ON(1);
1773         }
1774         set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree, buf);
1775 }
1776
1777 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
1778 {
1779         /*
1780          * looks as though older kernels can get into trouble with
1781          * this code, they end up stuck in balance_dirty_pages forever
1782          */
1783         struct extent_io_tree *tree;
1784         u64 num_dirty;
1785         u64 start = 0;
1786         unsigned long thresh = 16 * 1024 * 1024;
1787         tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
1788
1789         if (current_is_pdflush())
1790                 return;
1791
1792         num_dirty = count_range_bits(tree, &start, (u64)-1,
1793                                      thresh, EXTENT_DIRTY);
1794         if (num_dirty > thresh) {
1795                 balance_dirty_pages_ratelimited_nr(
1796                                    root->fs_info->btree_inode->i_mapping, 1);
1797         }
1798         return;
1799 }
1800
1801 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
1802 {
1803         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
1804         int ret;
1805         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1806         if (ret == 0) {
1807                 buf->flags |= EXTENT_UPTODATE;
1808         }
1809         return ret;
1810 }
1811
1812 static struct extent_io_ops btree_extent_io_ops = {
1813         .writepage_io_hook = btree_writepage_io_hook,
1814         .readpage_end_io_hook = btree_readpage_end_io_hook,
1815         .submit_bio_hook = btree_submit_bio_hook,
1816         /* note we're sharing with inode.c for the merge bio hook */
1817         .merge_bio_hook = btrfs_merge_bio_hook,
1818 };