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Merge branch 'for-chris' of git://repo.or.cz/linux-btrfs-devel into integration
[~shefty/rdma-dev.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 <linux/ratelimit.h>
33 #include <asm/unaligned.h>
34 #include "compat.h"
35 #include "ctree.h"
36 #include "disk-io.h"
37 #include "transaction.h"
38 #include "btrfs_inode.h"
39 #include "volumes.h"
40 #include "print-tree.h"
41 #include "async-thread.h"
42 #include "locking.h"
43 #include "tree-log.h"
44 #include "free-space-cache.h"
45 #include "inode-map.h"
46
47 static struct extent_io_ops btree_extent_io_ops;
48 static void end_workqueue_fn(struct btrfs_work *work);
49 static void free_fs_root(struct btrfs_root *root);
50 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
51                                     int read_only);
52 static int btrfs_destroy_ordered_operations(struct btrfs_root *root);
53 static int btrfs_destroy_ordered_extents(struct btrfs_root *root);
54 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
55                                       struct btrfs_root *root);
56 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t);
57 static int btrfs_destroy_delalloc_inodes(struct btrfs_root *root);
58 static int btrfs_destroy_marked_extents(struct btrfs_root *root,
59                                         struct extent_io_tree *dirty_pages,
60                                         int mark);
61 static int btrfs_destroy_pinned_extent(struct btrfs_root *root,
62                                        struct extent_io_tree *pinned_extents);
63 static int btrfs_cleanup_transaction(struct btrfs_root *root);
64
65 /*
66  * end_io_wq structs are used to do processing in task context when an IO is
67  * complete.  This is used during reads to verify checksums, and it is used
68  * by writes to insert metadata for new file extents after IO is complete.
69  */
70 struct end_io_wq {
71         struct bio *bio;
72         bio_end_io_t *end_io;
73         void *private;
74         struct btrfs_fs_info *info;
75         int error;
76         int metadata;
77         struct list_head list;
78         struct btrfs_work work;
79 };
80
81 /*
82  * async submit bios are used to offload expensive checksumming
83  * onto the worker threads.  They checksum file and metadata bios
84  * just before they are sent down the IO stack.
85  */
86 struct async_submit_bio {
87         struct inode *inode;
88         struct bio *bio;
89         struct list_head list;
90         extent_submit_bio_hook_t *submit_bio_start;
91         extent_submit_bio_hook_t *submit_bio_done;
92         int rw;
93         int mirror_num;
94         unsigned long bio_flags;
95         /*
96          * bio_offset is optional, can be used if the pages in the bio
97          * can't tell us where in the file the bio should go
98          */
99         u64 bio_offset;
100         struct btrfs_work work;
101 };
102
103 /*
104  * Lockdep class keys for extent_buffer->lock's in this root.  For a given
105  * eb, the lockdep key is determined by the btrfs_root it belongs to and
106  * the level the eb occupies in the tree.
107  *
108  * Different roots are used for different purposes and may nest inside each
109  * other and they require separate keysets.  As lockdep keys should be
110  * static, assign keysets according to the purpose of the root as indicated
111  * by btrfs_root->objectid.  This ensures that all special purpose roots
112  * have separate keysets.
113  *
114  * Lock-nesting across peer nodes is always done with the immediate parent
115  * node locked thus preventing deadlock.  As lockdep doesn't know this, use
116  * subclass to avoid triggering lockdep warning in such cases.
117  *
118  * The key is set by the readpage_end_io_hook after the buffer has passed
119  * csum validation but before the pages are unlocked.  It is also set by
120  * btrfs_init_new_buffer on freshly allocated blocks.
121  *
122  * We also add a check to make sure the highest level of the tree is the
123  * same as our lockdep setup here.  If BTRFS_MAX_LEVEL changes, this code
124  * needs update as well.
125  */
126 #ifdef CONFIG_DEBUG_LOCK_ALLOC
127 # if BTRFS_MAX_LEVEL != 8
128 #  error
129 # endif
130
131 static struct btrfs_lockdep_keyset {
132         u64                     id;             /* root objectid */
133         const char              *name_stem;     /* lock name stem */
134         char                    names[BTRFS_MAX_LEVEL + 1][20];
135         struct lock_class_key   keys[BTRFS_MAX_LEVEL + 1];
136 } btrfs_lockdep_keysets[] = {
137         { .id = BTRFS_ROOT_TREE_OBJECTID,       .name_stem = "root"     },
138         { .id = BTRFS_EXTENT_TREE_OBJECTID,     .name_stem = "extent"   },
139         { .id = BTRFS_CHUNK_TREE_OBJECTID,      .name_stem = "chunk"    },
140         { .id = BTRFS_DEV_TREE_OBJECTID,        .name_stem = "dev"      },
141         { .id = BTRFS_FS_TREE_OBJECTID,         .name_stem = "fs"       },
142         { .id = BTRFS_CSUM_TREE_OBJECTID,       .name_stem = "csum"     },
143         { .id = BTRFS_ORPHAN_OBJECTID,          .name_stem = "orphan"   },
144         { .id = BTRFS_TREE_LOG_OBJECTID,        .name_stem = "log"      },
145         { .id = BTRFS_TREE_RELOC_OBJECTID,      .name_stem = "treloc"   },
146         { .id = BTRFS_DATA_RELOC_TREE_OBJECTID, .name_stem = "dreloc"   },
147         { .id = 0,                              .name_stem = "tree"     },
148 };
149
150 void __init btrfs_init_lockdep(void)
151 {
152         int i, j;
153
154         /* initialize lockdep class names */
155         for (i = 0; i < ARRAY_SIZE(btrfs_lockdep_keysets); i++) {
156                 struct btrfs_lockdep_keyset *ks = &btrfs_lockdep_keysets[i];
157
158                 for (j = 0; j < ARRAY_SIZE(ks->names); j++)
159                         snprintf(ks->names[j], sizeof(ks->names[j]),
160                                  "btrfs-%s-%02d", ks->name_stem, j);
161         }
162 }
163
164 void btrfs_set_buffer_lockdep_class(u64 objectid, struct extent_buffer *eb,
165                                     int level)
166 {
167         struct btrfs_lockdep_keyset *ks;
168
169         BUG_ON(level >= ARRAY_SIZE(ks->keys));
170
171         /* find the matching keyset, id 0 is the default entry */
172         for (ks = btrfs_lockdep_keysets; ks->id; ks++)
173                 if (ks->id == objectid)
174                         break;
175
176         lockdep_set_class_and_name(&eb->lock,
177                                    &ks->keys[level], ks->names[level]);
178 }
179
180 #endif
181
182 /*
183  * extents on the btree inode are pretty simple, there's one extent
184  * that covers the entire device
185  */
186 static struct extent_map *btree_get_extent(struct inode *inode,
187                 struct page *page, size_t pg_offset, u64 start, u64 len,
188                 int create)
189 {
190         struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
191         struct extent_map *em;
192         int ret;
193
194         read_lock(&em_tree->lock);
195         em = lookup_extent_mapping(em_tree, start, len);
196         if (em) {
197                 em->bdev =
198                         BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
199                 read_unlock(&em_tree->lock);
200                 goto out;
201         }
202         read_unlock(&em_tree->lock);
203
204         em = alloc_extent_map();
205         if (!em) {
206                 em = ERR_PTR(-ENOMEM);
207                 goto out;
208         }
209         em->start = 0;
210         em->len = (u64)-1;
211         em->block_len = (u64)-1;
212         em->block_start = 0;
213         em->bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
214
215         write_lock(&em_tree->lock);
216         ret = add_extent_mapping(em_tree, em);
217         if (ret == -EEXIST) {
218                 u64 failed_start = em->start;
219                 u64 failed_len = em->len;
220
221                 free_extent_map(em);
222                 em = lookup_extent_mapping(em_tree, start, len);
223                 if (em) {
224                         ret = 0;
225                 } else {
226                         em = lookup_extent_mapping(em_tree, failed_start,
227                                                    failed_len);
228                         ret = -EIO;
229                 }
230         } else if (ret) {
231                 free_extent_map(em);
232                 em = NULL;
233         }
234         write_unlock(&em_tree->lock);
235
236         if (ret)
237                 em = ERR_PTR(ret);
238 out:
239         return em;
240 }
241
242 u32 btrfs_csum_data(struct btrfs_root *root, char *data, u32 seed, size_t len)
243 {
244         return crc32c(seed, data, len);
245 }
246
247 void btrfs_csum_final(u32 crc, char *result)
248 {
249         put_unaligned_le32(~crc, result);
250 }
251
252 /*
253  * compute the csum for a btree block, and either verify it or write it
254  * into the csum field of the block.
255  */
256 static int csum_tree_block(struct btrfs_root *root, struct extent_buffer *buf,
257                            int verify)
258 {
259         u16 csum_size = btrfs_super_csum_size(root->fs_info->super_copy);
260         char *result = NULL;
261         unsigned long len;
262         unsigned long cur_len;
263         unsigned long offset = BTRFS_CSUM_SIZE;
264         char *kaddr;
265         unsigned long map_start;
266         unsigned long map_len;
267         int err;
268         u32 crc = ~(u32)0;
269         unsigned long inline_result;
270
271         len = buf->len - offset;
272         while (len > 0) {
273                 err = map_private_extent_buffer(buf, offset, 32,
274                                         &kaddr, &map_start, &map_len);
275                 if (err)
276                         return 1;
277                 cur_len = min(len, map_len - (offset - map_start));
278                 crc = btrfs_csum_data(root, kaddr + offset - map_start,
279                                       crc, cur_len);
280                 len -= cur_len;
281                 offset += cur_len;
282         }
283         if (csum_size > sizeof(inline_result)) {
284                 result = kzalloc(csum_size * sizeof(char), GFP_NOFS);
285                 if (!result)
286                         return 1;
287         } else {
288                 result = (char *)&inline_result;
289         }
290
291         btrfs_csum_final(crc, result);
292
293         if (verify) {
294                 if (memcmp_extent_buffer(buf, result, 0, csum_size)) {
295                         u32 val;
296                         u32 found = 0;
297                         memcpy(&found, result, csum_size);
298
299                         read_extent_buffer(buf, &val, 0, csum_size);
300                         printk_ratelimited(KERN_INFO "btrfs: %s checksum verify "
301                                        "failed on %llu wanted %X found %X "
302                                        "level %d\n",
303                                        root->fs_info->sb->s_id,
304                                        (unsigned long long)buf->start, val, found,
305                                        btrfs_header_level(buf));
306                         if (result != (char *)&inline_result)
307                                 kfree(result);
308                         return 1;
309                 }
310         } else {
311                 write_extent_buffer(buf, result, 0, csum_size);
312         }
313         if (result != (char *)&inline_result)
314                 kfree(result);
315         return 0;
316 }
317
318 /*
319  * we can't consider a given block up to date unless the transid of the
320  * block matches the transid in the parent node's pointer.  This is how we
321  * detect blocks that either didn't get written at all or got written
322  * in the wrong place.
323  */
324 static int verify_parent_transid(struct extent_io_tree *io_tree,
325                                  struct extent_buffer *eb, u64 parent_transid)
326 {
327         struct extent_state *cached_state = NULL;
328         int ret;
329
330         if (!parent_transid || btrfs_header_generation(eb) == parent_transid)
331                 return 0;
332
333         lock_extent_bits(io_tree, eb->start, eb->start + eb->len - 1,
334                          0, &cached_state, GFP_NOFS);
335         if (extent_buffer_uptodate(io_tree, eb, cached_state) &&
336             btrfs_header_generation(eb) == parent_transid) {
337                 ret = 0;
338                 goto out;
339         }
340         printk_ratelimited("parent transid verify failed on %llu wanted %llu "
341                        "found %llu\n",
342                        (unsigned long long)eb->start,
343                        (unsigned long long)parent_transid,
344                        (unsigned long long)btrfs_header_generation(eb));
345         ret = 1;
346         clear_extent_buffer_uptodate(io_tree, eb, &cached_state);
347 out:
348         unlock_extent_cached(io_tree, eb->start, eb->start + eb->len - 1,
349                              &cached_state, GFP_NOFS);
350         return ret;
351 }
352
353 /*
354  * helper to read a given tree block, doing retries as required when
355  * the checksums don't match and we have alternate mirrors to try.
356  */
357 static int btree_read_extent_buffer_pages(struct btrfs_root *root,
358                                           struct extent_buffer *eb,
359                                           u64 start, u64 parent_transid)
360 {
361         struct extent_io_tree *io_tree;
362         int ret;
363         int num_copies = 0;
364         int mirror_num = 0;
365
366         clear_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
367         io_tree = &BTRFS_I(root->fs_info->btree_inode)->io_tree;
368         while (1) {
369                 ret = read_extent_buffer_pages(io_tree, eb, start,
370                                                WAIT_COMPLETE,
371                                                btree_get_extent, mirror_num);
372                 if (!ret &&
373                     !verify_parent_transid(io_tree, eb, parent_transid))
374                         return ret;
375
376                 /*
377                  * This buffer's crc is fine, but its contents are corrupted, so
378                  * there is no reason to read the other copies, they won't be
379                  * any less wrong.
380                  */
381                 if (test_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags))
382                         return ret;
383
384                 num_copies = btrfs_num_copies(&root->fs_info->mapping_tree,
385                                               eb->start, eb->len);
386                 if (num_copies == 1)
387                         return ret;
388
389                 mirror_num++;
390                 if (mirror_num > num_copies)
391                         return ret;
392         }
393         return -EIO;
394 }
395
396 /*
397  * checksum a dirty tree block before IO.  This has extra checks to make sure
398  * we only fill in the checksum field in the first page of a multi-page block
399  */
400
401 static int csum_dirty_buffer(struct btrfs_root *root, struct page *page)
402 {
403         struct extent_io_tree *tree;
404         u64 start = (u64)page->index << PAGE_CACHE_SHIFT;
405         u64 found_start;
406         unsigned long len;
407         struct extent_buffer *eb;
408         int ret;
409
410         tree = &BTRFS_I(page->mapping->host)->io_tree;
411
412         if (page->private == EXTENT_PAGE_PRIVATE) {
413                 WARN_ON(1);
414                 goto out;
415         }
416         if (!page->private) {
417                 WARN_ON(1);
418                 goto out;
419         }
420         len = page->private >> 2;
421         WARN_ON(len == 0);
422
423         eb = alloc_extent_buffer(tree, start, len, page);
424         if (eb == NULL) {
425                 WARN_ON(1);
426                 goto out;
427         }
428         ret = btree_read_extent_buffer_pages(root, eb, start + PAGE_CACHE_SIZE,
429                                              btrfs_header_generation(eb));
430         BUG_ON(ret);
431         WARN_ON(!btrfs_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN));
432
433         found_start = btrfs_header_bytenr(eb);
434         if (found_start != start) {
435                 WARN_ON(1);
436                 goto err;
437         }
438         if (eb->first_page != page) {
439                 WARN_ON(1);
440                 goto err;
441         }
442         if (!PageUptodate(page)) {
443                 WARN_ON(1);
444                 goto err;
445         }
446         csum_tree_block(root, eb, 0);
447 err:
448         free_extent_buffer(eb);
449 out:
450         return 0;
451 }
452
453 static int check_tree_block_fsid(struct btrfs_root *root,
454                                  struct extent_buffer *eb)
455 {
456         struct btrfs_fs_devices *fs_devices = root->fs_info->fs_devices;
457         u8 fsid[BTRFS_UUID_SIZE];
458         int ret = 1;
459
460         read_extent_buffer(eb, fsid, (unsigned long)btrfs_header_fsid(eb),
461                            BTRFS_FSID_SIZE);
462         while (fs_devices) {
463                 if (!memcmp(fsid, fs_devices->fsid, BTRFS_FSID_SIZE)) {
464                         ret = 0;
465                         break;
466                 }
467                 fs_devices = fs_devices->seed;
468         }
469         return ret;
470 }
471
472 #define CORRUPT(reason, eb, root, slot)                         \
473         printk(KERN_CRIT "btrfs: corrupt leaf, %s: block=%llu," \
474                "root=%llu, slot=%d\n", reason,                  \
475                (unsigned long long)btrfs_header_bytenr(eb),     \
476                (unsigned long long)root->objectid, slot)
477
478 static noinline int check_leaf(struct btrfs_root *root,
479                                struct extent_buffer *leaf)
480 {
481         struct btrfs_key key;
482         struct btrfs_key leaf_key;
483         u32 nritems = btrfs_header_nritems(leaf);
484         int slot;
485
486         if (nritems == 0)
487                 return 0;
488
489         /* Check the 0 item */
490         if (btrfs_item_offset_nr(leaf, 0) + btrfs_item_size_nr(leaf, 0) !=
491             BTRFS_LEAF_DATA_SIZE(root)) {
492                 CORRUPT("invalid item offset size pair", leaf, root, 0);
493                 return -EIO;
494         }
495
496         /*
497          * Check to make sure each items keys are in the correct order and their
498          * offsets make sense.  We only have to loop through nritems-1 because
499          * we check the current slot against the next slot, which verifies the
500          * next slot's offset+size makes sense and that the current's slot
501          * offset is correct.
502          */
503         for (slot = 0; slot < nritems - 1; slot++) {
504                 btrfs_item_key_to_cpu(leaf, &leaf_key, slot);
505                 btrfs_item_key_to_cpu(leaf, &key, slot + 1);
506
507                 /* Make sure the keys are in the right order */
508                 if (btrfs_comp_cpu_keys(&leaf_key, &key) >= 0) {
509                         CORRUPT("bad key order", leaf, root, slot);
510                         return -EIO;
511                 }
512
513                 /*
514                  * Make sure the offset and ends are right, remember that the
515                  * item data starts at the end of the leaf and grows towards the
516                  * front.
517                  */
518                 if (btrfs_item_offset_nr(leaf, slot) !=
519                         btrfs_item_end_nr(leaf, slot + 1)) {
520                         CORRUPT("slot offset bad", leaf, root, slot);
521                         return -EIO;
522                 }
523
524                 /*
525                  * Check to make sure that we don't point outside of the leaf,
526                  * just incase all the items are consistent to eachother, but
527                  * all point outside of the leaf.
528                  */
529                 if (btrfs_item_end_nr(leaf, slot) >
530                     BTRFS_LEAF_DATA_SIZE(root)) {
531                         CORRUPT("slot end outside of leaf", leaf, root, slot);
532                         return -EIO;
533                 }
534         }
535
536         return 0;
537 }
538
539 static int btree_readpage_end_io_hook(struct page *page, u64 start, u64 end,
540                                struct extent_state *state)
541 {
542         struct extent_io_tree *tree;
543         u64 found_start;
544         int found_level;
545         unsigned long len;
546         struct extent_buffer *eb;
547         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
548         int ret = 0;
549
550         tree = &BTRFS_I(page->mapping->host)->io_tree;
551         if (page->private == EXTENT_PAGE_PRIVATE)
552                 goto out;
553         if (!page->private)
554                 goto out;
555
556         len = page->private >> 2;
557         WARN_ON(len == 0);
558
559         eb = alloc_extent_buffer(tree, start, len, page);
560         if (eb == NULL) {
561                 ret = -EIO;
562                 goto out;
563         }
564
565         found_start = btrfs_header_bytenr(eb);
566         if (found_start != start) {
567                 printk_ratelimited(KERN_INFO "btrfs bad tree block start "
568                                "%llu %llu\n",
569                                (unsigned long long)found_start,
570                                (unsigned long long)eb->start);
571                 ret = -EIO;
572                 goto err;
573         }
574         if (eb->first_page != page) {
575                 printk(KERN_INFO "btrfs bad first page %lu %lu\n",
576                        eb->first_page->index, page->index);
577                 WARN_ON(1);
578                 ret = -EIO;
579                 goto err;
580         }
581         if (check_tree_block_fsid(root, eb)) {
582                 printk_ratelimited(KERN_INFO "btrfs bad fsid on block %llu\n",
583                                (unsigned long long)eb->start);
584                 ret = -EIO;
585                 goto err;
586         }
587         found_level = btrfs_header_level(eb);
588
589         btrfs_set_buffer_lockdep_class(btrfs_header_owner(eb),
590                                        eb, found_level);
591
592         ret = csum_tree_block(root, eb, 1);
593         if (ret) {
594                 ret = -EIO;
595                 goto err;
596         }
597
598         /*
599          * If this is a leaf block and it is corrupt, set the corrupt bit so
600          * that we don't try and read the other copies of this block, just
601          * return -EIO.
602          */
603         if (found_level == 0 && check_leaf(root, eb)) {
604                 set_bit(EXTENT_BUFFER_CORRUPT, &eb->bflags);
605                 ret = -EIO;
606         }
607
608         end = min_t(u64, eb->len, PAGE_CACHE_SIZE);
609         end = eb->start + end - 1;
610 err:
611         if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
612                 clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
613                 btree_readahead_hook(root, eb, eb->start, ret);
614         }
615
616         free_extent_buffer(eb);
617 out:
618         return ret;
619 }
620
621 static int btree_io_failed_hook(struct bio *failed_bio,
622                          struct page *page, u64 start, u64 end,
623                          int mirror_num, struct extent_state *state)
624 {
625         struct extent_io_tree *tree;
626         unsigned long len;
627         struct extent_buffer *eb;
628         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
629
630         tree = &BTRFS_I(page->mapping->host)->io_tree;
631         if (page->private == EXTENT_PAGE_PRIVATE)
632                 goto out;
633         if (!page->private)
634                 goto out;
635
636         len = page->private >> 2;
637         WARN_ON(len == 0);
638
639         eb = alloc_extent_buffer(tree, start, len, page);
640         if (eb == NULL)
641                 goto out;
642
643         if (test_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags)) {
644                 clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags);
645                 btree_readahead_hook(root, eb, eb->start, -EIO);
646         }
647         free_extent_buffer(eb);
648
649 out:
650         return -EIO;    /* we fixed nothing */
651 }
652
653 static void end_workqueue_bio(struct bio *bio, int err)
654 {
655         struct end_io_wq *end_io_wq = bio->bi_private;
656         struct btrfs_fs_info *fs_info;
657
658         fs_info = end_io_wq->info;
659         end_io_wq->error = err;
660         end_io_wq->work.func = end_workqueue_fn;
661         end_io_wq->work.flags = 0;
662
663         if (bio->bi_rw & REQ_WRITE) {
664                 if (end_io_wq->metadata == 1)
665                         btrfs_queue_worker(&fs_info->endio_meta_write_workers,
666                                            &end_io_wq->work);
667                 else if (end_io_wq->metadata == 2)
668                         btrfs_queue_worker(&fs_info->endio_freespace_worker,
669                                            &end_io_wq->work);
670                 else
671                         btrfs_queue_worker(&fs_info->endio_write_workers,
672                                            &end_io_wq->work);
673         } else {
674                 if (end_io_wq->metadata)
675                         btrfs_queue_worker(&fs_info->endio_meta_workers,
676                                            &end_io_wq->work);
677                 else
678                         btrfs_queue_worker(&fs_info->endio_workers,
679                                            &end_io_wq->work);
680         }
681 }
682
683 /*
684  * For the metadata arg you want
685  *
686  * 0 - if data
687  * 1 - if normal metadta
688  * 2 - if writing to the free space cache area
689  */
690 int btrfs_bio_wq_end_io(struct btrfs_fs_info *info, struct bio *bio,
691                         int metadata)
692 {
693         struct end_io_wq *end_io_wq;
694         end_io_wq = kmalloc(sizeof(*end_io_wq), GFP_NOFS);
695         if (!end_io_wq)
696                 return -ENOMEM;
697
698         end_io_wq->private = bio->bi_private;
699         end_io_wq->end_io = bio->bi_end_io;
700         end_io_wq->info = info;
701         end_io_wq->error = 0;
702         end_io_wq->bio = bio;
703         end_io_wq->metadata = metadata;
704
705         bio->bi_private = end_io_wq;
706         bio->bi_end_io = end_workqueue_bio;
707         return 0;
708 }
709
710 unsigned long btrfs_async_submit_limit(struct btrfs_fs_info *info)
711 {
712         unsigned long limit = min_t(unsigned long,
713                                     info->workers.max_workers,
714                                     info->fs_devices->open_devices);
715         return 256 * limit;
716 }
717
718 static void run_one_async_start(struct btrfs_work *work)
719 {
720         struct async_submit_bio *async;
721
722         async = container_of(work, struct  async_submit_bio, work);
723         async->submit_bio_start(async->inode, async->rw, async->bio,
724                                async->mirror_num, async->bio_flags,
725                                async->bio_offset);
726 }
727
728 static void run_one_async_done(struct btrfs_work *work)
729 {
730         struct btrfs_fs_info *fs_info;
731         struct async_submit_bio *async;
732         int limit;
733
734         async = container_of(work, struct  async_submit_bio, work);
735         fs_info = BTRFS_I(async->inode)->root->fs_info;
736
737         limit = btrfs_async_submit_limit(fs_info);
738         limit = limit * 2 / 3;
739
740         atomic_dec(&fs_info->nr_async_submits);
741
742         if (atomic_read(&fs_info->nr_async_submits) < limit &&
743             waitqueue_active(&fs_info->async_submit_wait))
744                 wake_up(&fs_info->async_submit_wait);
745
746         async->submit_bio_done(async->inode, async->rw, async->bio,
747                                async->mirror_num, async->bio_flags,
748                                async->bio_offset);
749 }
750
751 static void run_one_async_free(struct btrfs_work *work)
752 {
753         struct async_submit_bio *async;
754
755         async = container_of(work, struct  async_submit_bio, work);
756         kfree(async);
757 }
758
759 int btrfs_wq_submit_bio(struct btrfs_fs_info *fs_info, struct inode *inode,
760                         int rw, struct bio *bio, int mirror_num,
761                         unsigned long bio_flags,
762                         u64 bio_offset,
763                         extent_submit_bio_hook_t *submit_bio_start,
764                         extent_submit_bio_hook_t *submit_bio_done)
765 {
766         struct async_submit_bio *async;
767
768         async = kmalloc(sizeof(*async), GFP_NOFS);
769         if (!async)
770                 return -ENOMEM;
771
772         async->inode = inode;
773         async->rw = rw;
774         async->bio = bio;
775         async->mirror_num = mirror_num;
776         async->submit_bio_start = submit_bio_start;
777         async->submit_bio_done = submit_bio_done;
778
779         async->work.func = run_one_async_start;
780         async->work.ordered_func = run_one_async_done;
781         async->work.ordered_free = run_one_async_free;
782
783         async->work.flags = 0;
784         async->bio_flags = bio_flags;
785         async->bio_offset = bio_offset;
786
787         atomic_inc(&fs_info->nr_async_submits);
788
789         if (rw & REQ_SYNC)
790                 btrfs_set_work_high_prio(&async->work);
791
792         btrfs_queue_worker(&fs_info->workers, &async->work);
793
794         while (atomic_read(&fs_info->async_submit_draining) &&
795               atomic_read(&fs_info->nr_async_submits)) {
796                 wait_event(fs_info->async_submit_wait,
797                            (atomic_read(&fs_info->nr_async_submits) == 0));
798         }
799
800         return 0;
801 }
802
803 static int btree_csum_one_bio(struct bio *bio)
804 {
805         struct bio_vec *bvec = bio->bi_io_vec;
806         int bio_index = 0;
807         struct btrfs_root *root;
808
809         WARN_ON(bio->bi_vcnt <= 0);
810         while (bio_index < bio->bi_vcnt) {
811                 root = BTRFS_I(bvec->bv_page->mapping->host)->root;
812                 csum_dirty_buffer(root, bvec->bv_page);
813                 bio_index++;
814                 bvec++;
815         }
816         return 0;
817 }
818
819 static int __btree_submit_bio_start(struct inode *inode, int rw,
820                                     struct bio *bio, int mirror_num,
821                                     unsigned long bio_flags,
822                                     u64 bio_offset)
823 {
824         /*
825          * when we're called for a write, we're already in the async
826          * submission context.  Just jump into btrfs_map_bio
827          */
828         btree_csum_one_bio(bio);
829         return 0;
830 }
831
832 static int __btree_submit_bio_done(struct inode *inode, int rw, struct bio *bio,
833                                  int mirror_num, unsigned long bio_flags,
834                                  u64 bio_offset)
835 {
836         /*
837          * when we're called for a write, we're already in the async
838          * submission context.  Just jump into btrfs_map_bio
839          */
840         return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio, mirror_num, 1);
841 }
842
843 static int btree_submit_bio_hook(struct inode *inode, int rw, struct bio *bio,
844                                  int mirror_num, unsigned long bio_flags,
845                                  u64 bio_offset)
846 {
847         int ret;
848
849         ret = btrfs_bio_wq_end_io(BTRFS_I(inode)->root->fs_info,
850                                           bio, 1);
851         BUG_ON(ret);
852
853         if (!(rw & REQ_WRITE)) {
854                 /*
855                  * called for a read, do the setup so that checksum validation
856                  * can happen in the async kernel threads
857                  */
858                 return btrfs_map_bio(BTRFS_I(inode)->root, rw, bio,
859                                      mirror_num, 0);
860         }
861
862         /*
863          * kthread helpers are used to submit writes so that checksumming
864          * can happen in parallel across all CPUs
865          */
866         return btrfs_wq_submit_bio(BTRFS_I(inode)->root->fs_info,
867                                    inode, rw, bio, mirror_num, 0,
868                                    bio_offset,
869                                    __btree_submit_bio_start,
870                                    __btree_submit_bio_done);
871 }
872
873 #ifdef CONFIG_MIGRATION
874 static int btree_migratepage(struct address_space *mapping,
875                         struct page *newpage, struct page *page)
876 {
877         /*
878          * we can't safely write a btree page from here,
879          * we haven't done the locking hook
880          */
881         if (PageDirty(page))
882                 return -EAGAIN;
883         /*
884          * Buffers may be managed in a filesystem specific way.
885          * We must have no buffers or drop them.
886          */
887         if (page_has_private(page) &&
888             !try_to_release_page(page, GFP_KERNEL))
889                 return -EAGAIN;
890         return migrate_page(mapping, newpage, page);
891 }
892 #endif
893
894 static int btree_writepage(struct page *page, struct writeback_control *wbc)
895 {
896         struct extent_io_tree *tree;
897         struct btrfs_root *root = BTRFS_I(page->mapping->host)->root;
898         struct extent_buffer *eb;
899         int was_dirty;
900
901         tree = &BTRFS_I(page->mapping->host)->io_tree;
902         if (!(current->flags & PF_MEMALLOC)) {
903                 return extent_write_full_page(tree, page,
904                                               btree_get_extent, wbc);
905         }
906
907         redirty_page_for_writepage(wbc, page);
908         eb = btrfs_find_tree_block(root, page_offset(page), PAGE_CACHE_SIZE);
909         WARN_ON(!eb);
910
911         was_dirty = test_and_set_bit(EXTENT_BUFFER_DIRTY, &eb->bflags);
912         if (!was_dirty) {
913                 spin_lock(&root->fs_info->delalloc_lock);
914                 root->fs_info->dirty_metadata_bytes += PAGE_CACHE_SIZE;
915                 spin_unlock(&root->fs_info->delalloc_lock);
916         }
917         free_extent_buffer(eb);
918
919         unlock_page(page);
920         return 0;
921 }
922
923 static int btree_writepages(struct address_space *mapping,
924                             struct writeback_control *wbc)
925 {
926         struct extent_io_tree *tree;
927         tree = &BTRFS_I(mapping->host)->io_tree;
928         if (wbc->sync_mode == WB_SYNC_NONE) {
929                 struct btrfs_root *root = BTRFS_I(mapping->host)->root;
930                 u64 num_dirty;
931                 unsigned long thresh = 32 * 1024 * 1024;
932
933                 if (wbc->for_kupdate)
934                         return 0;
935
936                 /* this is a bit racy, but that's ok */
937                 num_dirty = root->fs_info->dirty_metadata_bytes;
938                 if (num_dirty < thresh)
939                         return 0;
940         }
941         return extent_writepages(tree, mapping, btree_get_extent, wbc);
942 }
943
944 static int btree_readpage(struct file *file, struct page *page)
945 {
946         struct extent_io_tree *tree;
947         tree = &BTRFS_I(page->mapping->host)->io_tree;
948         return extent_read_full_page(tree, page, btree_get_extent, 0);
949 }
950
951 static int btree_releasepage(struct page *page, gfp_t gfp_flags)
952 {
953         struct extent_io_tree *tree;
954         struct extent_map_tree *map;
955         int ret;
956
957         if (PageWriteback(page) || PageDirty(page))
958                 return 0;
959
960         tree = &BTRFS_I(page->mapping->host)->io_tree;
961         map = &BTRFS_I(page->mapping->host)->extent_tree;
962
963         ret = try_release_extent_state(map, tree, page, gfp_flags);
964         if (!ret)
965                 return 0;
966
967         ret = try_release_extent_buffer(tree, page);
968         if (ret == 1) {
969                 ClearPagePrivate(page);
970                 set_page_private(page, 0);
971                 page_cache_release(page);
972         }
973
974         return ret;
975 }
976
977 static void btree_invalidatepage(struct page *page, unsigned long offset)
978 {
979         struct extent_io_tree *tree;
980         tree = &BTRFS_I(page->mapping->host)->io_tree;
981         extent_invalidatepage(tree, page, offset);
982         btree_releasepage(page, GFP_NOFS);
983         if (PagePrivate(page)) {
984                 printk(KERN_WARNING "btrfs warning page private not zero "
985                        "on page %llu\n", (unsigned long long)page_offset(page));
986                 ClearPagePrivate(page);
987                 set_page_private(page, 0);
988                 page_cache_release(page);
989         }
990 }
991
992 static const struct address_space_operations btree_aops = {
993         .readpage       = btree_readpage,
994         .writepage      = btree_writepage,
995         .writepages     = btree_writepages,
996         .releasepage    = btree_releasepage,
997         .invalidatepage = btree_invalidatepage,
998 #ifdef CONFIG_MIGRATION
999         .migratepage    = btree_migratepage,
1000 #endif
1001 };
1002
1003 int readahead_tree_block(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1004                          u64 parent_transid)
1005 {
1006         struct extent_buffer *buf = NULL;
1007         struct inode *btree_inode = root->fs_info->btree_inode;
1008         int ret = 0;
1009
1010         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1011         if (!buf)
1012                 return 0;
1013         read_extent_buffer_pages(&BTRFS_I(btree_inode)->io_tree,
1014                                  buf, 0, WAIT_NONE, btree_get_extent, 0);
1015         free_extent_buffer(buf);
1016         return ret;
1017 }
1018
1019 int reada_tree_block_flagged(struct btrfs_root *root, u64 bytenr, u32 blocksize,
1020                          int mirror_num, struct extent_buffer **eb)
1021 {
1022         struct extent_buffer *buf = NULL;
1023         struct inode *btree_inode = root->fs_info->btree_inode;
1024         struct extent_io_tree *io_tree = &BTRFS_I(btree_inode)->io_tree;
1025         int ret;
1026
1027         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1028         if (!buf)
1029                 return 0;
1030
1031         set_bit(EXTENT_BUFFER_READAHEAD, &buf->bflags);
1032
1033         ret = read_extent_buffer_pages(io_tree, buf, 0, WAIT_PAGE_LOCK,
1034                                        btree_get_extent, mirror_num);
1035         if (ret) {
1036                 free_extent_buffer(buf);
1037                 return ret;
1038         }
1039
1040         if (test_bit(EXTENT_BUFFER_CORRUPT, &buf->bflags)) {
1041                 free_extent_buffer(buf);
1042                 return -EIO;
1043         } else if (extent_buffer_uptodate(io_tree, buf, NULL)) {
1044                 *eb = buf;
1045         } else {
1046                 free_extent_buffer(buf);
1047         }
1048         return 0;
1049 }
1050
1051 struct extent_buffer *btrfs_find_tree_block(struct btrfs_root *root,
1052                                             u64 bytenr, u32 blocksize)
1053 {
1054         struct inode *btree_inode = root->fs_info->btree_inode;
1055         struct extent_buffer *eb;
1056         eb = find_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1057                                 bytenr, blocksize);
1058         return eb;
1059 }
1060
1061 struct extent_buffer *btrfs_find_create_tree_block(struct btrfs_root *root,
1062                                                  u64 bytenr, u32 blocksize)
1063 {
1064         struct inode *btree_inode = root->fs_info->btree_inode;
1065         struct extent_buffer *eb;
1066
1067         eb = alloc_extent_buffer(&BTRFS_I(btree_inode)->io_tree,
1068                                  bytenr, blocksize, NULL);
1069         return eb;
1070 }
1071
1072
1073 int btrfs_write_tree_block(struct extent_buffer *buf)
1074 {
1075         return filemap_fdatawrite_range(buf->first_page->mapping, buf->start,
1076                                         buf->start + buf->len - 1);
1077 }
1078
1079 int btrfs_wait_tree_block_writeback(struct extent_buffer *buf)
1080 {
1081         return filemap_fdatawait_range(buf->first_page->mapping,
1082                                        buf->start, buf->start + buf->len - 1);
1083 }
1084
1085 struct extent_buffer *read_tree_block(struct btrfs_root *root, u64 bytenr,
1086                                       u32 blocksize, u64 parent_transid)
1087 {
1088         struct extent_buffer *buf = NULL;
1089         int ret;
1090
1091         buf = btrfs_find_create_tree_block(root, bytenr, blocksize);
1092         if (!buf)
1093                 return NULL;
1094
1095         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
1096
1097         if (ret == 0)
1098                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
1099         return buf;
1100
1101 }
1102
1103 int clean_tree_block(struct btrfs_trans_handle *trans, struct btrfs_root *root,
1104                      struct extent_buffer *buf)
1105 {
1106         struct inode *btree_inode = root->fs_info->btree_inode;
1107         if (btrfs_header_generation(buf) ==
1108             root->fs_info->running_transaction->transid) {
1109                 btrfs_assert_tree_locked(buf);
1110
1111                 if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &buf->bflags)) {
1112                         spin_lock(&root->fs_info->delalloc_lock);
1113                         if (root->fs_info->dirty_metadata_bytes >= buf->len)
1114                                 root->fs_info->dirty_metadata_bytes -= buf->len;
1115                         else
1116                                 WARN_ON(1);
1117                         spin_unlock(&root->fs_info->delalloc_lock);
1118                 }
1119
1120                 /* ugh, clear_extent_buffer_dirty needs to lock the page */
1121                 btrfs_set_lock_blocking(buf);
1122                 clear_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
1123                                           buf);
1124         }
1125         return 0;
1126 }
1127
1128 static int __setup_root(u32 nodesize, u32 leafsize, u32 sectorsize,
1129                         u32 stripesize, struct btrfs_root *root,
1130                         struct btrfs_fs_info *fs_info,
1131                         u64 objectid)
1132 {
1133         root->node = NULL;
1134         root->commit_root = NULL;
1135         root->sectorsize = sectorsize;
1136         root->nodesize = nodesize;
1137         root->leafsize = leafsize;
1138         root->stripesize = stripesize;
1139         root->ref_cows = 0;
1140         root->track_dirty = 0;
1141         root->in_radix = 0;
1142         root->orphan_item_inserted = 0;
1143         root->orphan_cleanup_state = 0;
1144
1145         root->fs_info = fs_info;
1146         root->objectid = objectid;
1147         root->last_trans = 0;
1148         root->highest_objectid = 0;
1149         root->name = NULL;
1150         root->inode_tree = RB_ROOT;
1151         INIT_RADIX_TREE(&root->delayed_nodes_tree, GFP_ATOMIC);
1152         root->block_rsv = NULL;
1153         root->orphan_block_rsv = NULL;
1154
1155         INIT_LIST_HEAD(&root->dirty_list);
1156         INIT_LIST_HEAD(&root->orphan_list);
1157         INIT_LIST_HEAD(&root->root_list);
1158         spin_lock_init(&root->orphan_lock);
1159         spin_lock_init(&root->inode_lock);
1160         spin_lock_init(&root->accounting_lock);
1161         mutex_init(&root->objectid_mutex);
1162         mutex_init(&root->log_mutex);
1163         init_waitqueue_head(&root->log_writer_wait);
1164         init_waitqueue_head(&root->log_commit_wait[0]);
1165         init_waitqueue_head(&root->log_commit_wait[1]);
1166         atomic_set(&root->log_commit[0], 0);
1167         atomic_set(&root->log_commit[1], 0);
1168         atomic_set(&root->log_writers, 0);
1169         root->log_batch = 0;
1170         root->log_transid = 0;
1171         root->last_log_commit = 0;
1172         extent_io_tree_init(&root->dirty_log_pages,
1173                              fs_info->btree_inode->i_mapping);
1174
1175         memset(&root->root_key, 0, sizeof(root->root_key));
1176         memset(&root->root_item, 0, sizeof(root->root_item));
1177         memset(&root->defrag_progress, 0, sizeof(root->defrag_progress));
1178         memset(&root->root_kobj, 0, sizeof(root->root_kobj));
1179         root->defrag_trans_start = fs_info->generation;
1180         init_completion(&root->kobj_unregister);
1181         root->defrag_running = 0;
1182         root->root_key.objectid = objectid;
1183         root->anon_dev = 0;
1184         return 0;
1185 }
1186
1187 static int find_and_setup_root(struct btrfs_root *tree_root,
1188                                struct btrfs_fs_info *fs_info,
1189                                u64 objectid,
1190                                struct btrfs_root *root)
1191 {
1192         int ret;
1193         u32 blocksize;
1194         u64 generation;
1195
1196         __setup_root(tree_root->nodesize, tree_root->leafsize,
1197                      tree_root->sectorsize, tree_root->stripesize,
1198                      root, fs_info, objectid);
1199         ret = btrfs_find_last_root(tree_root, objectid,
1200                                    &root->root_item, &root->root_key);
1201         if (ret > 0)
1202                 return -ENOENT;
1203         BUG_ON(ret);
1204
1205         generation = btrfs_root_generation(&root->root_item);
1206         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1207         root->commit_root = NULL;
1208         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1209                                      blocksize, generation);
1210         if (!root->node || !btrfs_buffer_uptodate(root->node, generation)) {
1211                 free_extent_buffer(root->node);
1212                 root->node = NULL;
1213                 return -EIO;
1214         }
1215         root->commit_root = btrfs_root_node(root);
1216         return 0;
1217 }
1218
1219 static struct btrfs_root *alloc_log_tree(struct btrfs_trans_handle *trans,
1220                                          struct btrfs_fs_info *fs_info)
1221 {
1222         struct btrfs_root *root;
1223         struct btrfs_root *tree_root = fs_info->tree_root;
1224         struct extent_buffer *leaf;
1225
1226         root = kzalloc(sizeof(*root), GFP_NOFS);
1227         if (!root)
1228                 return ERR_PTR(-ENOMEM);
1229
1230         __setup_root(tree_root->nodesize, tree_root->leafsize,
1231                      tree_root->sectorsize, tree_root->stripesize,
1232                      root, fs_info, BTRFS_TREE_LOG_OBJECTID);
1233
1234         root->root_key.objectid = BTRFS_TREE_LOG_OBJECTID;
1235         root->root_key.type = BTRFS_ROOT_ITEM_KEY;
1236         root->root_key.offset = BTRFS_TREE_LOG_OBJECTID;
1237         /*
1238          * log trees do not get reference counted because they go away
1239          * before a real commit is actually done.  They do store pointers
1240          * to file data extents, and those reference counts still get
1241          * updated (along with back refs to the log tree).
1242          */
1243         root->ref_cows = 0;
1244
1245         leaf = btrfs_alloc_free_block(trans, root, root->leafsize, 0,
1246                                       BTRFS_TREE_LOG_OBJECTID, NULL, 0, 0, 0);
1247         if (IS_ERR(leaf)) {
1248                 kfree(root);
1249                 return ERR_CAST(leaf);
1250         }
1251
1252         memset_extent_buffer(leaf, 0, 0, sizeof(struct btrfs_header));
1253         btrfs_set_header_bytenr(leaf, leaf->start);
1254         btrfs_set_header_generation(leaf, trans->transid);
1255         btrfs_set_header_backref_rev(leaf, BTRFS_MIXED_BACKREF_REV);
1256         btrfs_set_header_owner(leaf, BTRFS_TREE_LOG_OBJECTID);
1257         root->node = leaf;
1258
1259         write_extent_buffer(root->node, root->fs_info->fsid,
1260                             (unsigned long)btrfs_header_fsid(root->node),
1261                             BTRFS_FSID_SIZE);
1262         btrfs_mark_buffer_dirty(root->node);
1263         btrfs_tree_unlock(root->node);
1264         return root;
1265 }
1266
1267 int btrfs_init_log_root_tree(struct btrfs_trans_handle *trans,
1268                              struct btrfs_fs_info *fs_info)
1269 {
1270         struct btrfs_root *log_root;
1271
1272         log_root = alloc_log_tree(trans, fs_info);
1273         if (IS_ERR(log_root))
1274                 return PTR_ERR(log_root);
1275         WARN_ON(fs_info->log_root_tree);
1276         fs_info->log_root_tree = log_root;
1277         return 0;
1278 }
1279
1280 int btrfs_add_log_tree(struct btrfs_trans_handle *trans,
1281                        struct btrfs_root *root)
1282 {
1283         struct btrfs_root *log_root;
1284         struct btrfs_inode_item *inode_item;
1285
1286         log_root = alloc_log_tree(trans, root->fs_info);
1287         if (IS_ERR(log_root))
1288                 return PTR_ERR(log_root);
1289
1290         log_root->last_trans = trans->transid;
1291         log_root->root_key.offset = root->root_key.objectid;
1292
1293         inode_item = &log_root->root_item.inode;
1294         inode_item->generation = cpu_to_le64(1);
1295         inode_item->size = cpu_to_le64(3);
1296         inode_item->nlink = cpu_to_le32(1);
1297         inode_item->nbytes = cpu_to_le64(root->leafsize);
1298         inode_item->mode = cpu_to_le32(S_IFDIR | 0755);
1299
1300         btrfs_set_root_node(&log_root->root_item, log_root->node);
1301
1302         WARN_ON(root->log_root);
1303         root->log_root = log_root;
1304         root->log_transid = 0;
1305         root->last_log_commit = 0;
1306         return 0;
1307 }
1308
1309 struct btrfs_root *btrfs_read_fs_root_no_radix(struct btrfs_root *tree_root,
1310                                                struct btrfs_key *location)
1311 {
1312         struct btrfs_root *root;
1313         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1314         struct btrfs_path *path;
1315         struct extent_buffer *l;
1316         u64 generation;
1317         u32 blocksize;
1318         int ret = 0;
1319
1320         root = kzalloc(sizeof(*root), GFP_NOFS);
1321         if (!root)
1322                 return ERR_PTR(-ENOMEM);
1323         if (location->offset == (u64)-1) {
1324                 ret = find_and_setup_root(tree_root, fs_info,
1325                                           location->objectid, root);
1326                 if (ret) {
1327                         kfree(root);
1328                         return ERR_PTR(ret);
1329                 }
1330                 goto out;
1331         }
1332
1333         __setup_root(tree_root->nodesize, tree_root->leafsize,
1334                      tree_root->sectorsize, tree_root->stripesize,
1335                      root, fs_info, location->objectid);
1336
1337         path = btrfs_alloc_path();
1338         if (!path) {
1339                 kfree(root);
1340                 return ERR_PTR(-ENOMEM);
1341         }
1342         ret = btrfs_search_slot(NULL, tree_root, location, path, 0, 0);
1343         if (ret == 0) {
1344                 l = path->nodes[0];
1345                 read_extent_buffer(l, &root->root_item,
1346                                 btrfs_item_ptr_offset(l, path->slots[0]),
1347                                 sizeof(root->root_item));
1348                 memcpy(&root->root_key, location, sizeof(*location));
1349         }
1350         btrfs_free_path(path);
1351         if (ret) {
1352                 kfree(root);
1353                 if (ret > 0)
1354                         ret = -ENOENT;
1355                 return ERR_PTR(ret);
1356         }
1357
1358         generation = btrfs_root_generation(&root->root_item);
1359         blocksize = btrfs_level_size(root, btrfs_root_level(&root->root_item));
1360         root->node = read_tree_block(root, btrfs_root_bytenr(&root->root_item),
1361                                      blocksize, generation);
1362         root->commit_root = btrfs_root_node(root);
1363         BUG_ON(!root->node);
1364 out:
1365         if (location->objectid != BTRFS_TREE_LOG_OBJECTID) {
1366                 root->ref_cows = 1;
1367                 btrfs_check_and_init_root_item(&root->root_item);
1368         }
1369
1370         return root;
1371 }
1372
1373 struct btrfs_root *btrfs_read_fs_root_no_name(struct btrfs_fs_info *fs_info,
1374                                               struct btrfs_key *location)
1375 {
1376         struct btrfs_root *root;
1377         int ret;
1378
1379         if (location->objectid == BTRFS_ROOT_TREE_OBJECTID)
1380                 return fs_info->tree_root;
1381         if (location->objectid == BTRFS_EXTENT_TREE_OBJECTID)
1382                 return fs_info->extent_root;
1383         if (location->objectid == BTRFS_CHUNK_TREE_OBJECTID)
1384                 return fs_info->chunk_root;
1385         if (location->objectid == BTRFS_DEV_TREE_OBJECTID)
1386                 return fs_info->dev_root;
1387         if (location->objectid == BTRFS_CSUM_TREE_OBJECTID)
1388                 return fs_info->csum_root;
1389 again:
1390         spin_lock(&fs_info->fs_roots_radix_lock);
1391         root = radix_tree_lookup(&fs_info->fs_roots_radix,
1392                                  (unsigned long)location->objectid);
1393         spin_unlock(&fs_info->fs_roots_radix_lock);
1394         if (root)
1395                 return root;
1396
1397         root = btrfs_read_fs_root_no_radix(fs_info->tree_root, location);
1398         if (IS_ERR(root))
1399                 return root;
1400
1401         root->free_ino_ctl = kzalloc(sizeof(*root->free_ino_ctl), GFP_NOFS);
1402         root->free_ino_pinned = kzalloc(sizeof(*root->free_ino_pinned),
1403                                         GFP_NOFS);
1404         if (!root->free_ino_pinned || !root->free_ino_ctl) {
1405                 ret = -ENOMEM;
1406                 goto fail;
1407         }
1408
1409         btrfs_init_free_ino_ctl(root);
1410         mutex_init(&root->fs_commit_mutex);
1411         spin_lock_init(&root->cache_lock);
1412         init_waitqueue_head(&root->cache_wait);
1413
1414         ret = get_anon_bdev(&root->anon_dev);
1415         if (ret)
1416                 goto fail;
1417
1418         if (btrfs_root_refs(&root->root_item) == 0) {
1419                 ret = -ENOENT;
1420                 goto fail;
1421         }
1422
1423         ret = btrfs_find_orphan_item(fs_info->tree_root, location->objectid);
1424         if (ret < 0)
1425                 goto fail;
1426         if (ret == 0)
1427                 root->orphan_item_inserted = 1;
1428
1429         ret = radix_tree_preload(GFP_NOFS & ~__GFP_HIGHMEM);
1430         if (ret)
1431                 goto fail;
1432
1433         spin_lock(&fs_info->fs_roots_radix_lock);
1434         ret = radix_tree_insert(&fs_info->fs_roots_radix,
1435                                 (unsigned long)root->root_key.objectid,
1436                                 root);
1437         if (ret == 0)
1438                 root->in_radix = 1;
1439
1440         spin_unlock(&fs_info->fs_roots_radix_lock);
1441         radix_tree_preload_end();
1442         if (ret) {
1443                 if (ret == -EEXIST) {
1444                         free_fs_root(root);
1445                         goto again;
1446                 }
1447                 goto fail;
1448         }
1449
1450         ret = btrfs_find_dead_roots(fs_info->tree_root,
1451                                     root->root_key.objectid);
1452         WARN_ON(ret);
1453         return root;
1454 fail:
1455         free_fs_root(root);
1456         return ERR_PTR(ret);
1457 }
1458
1459 static int btrfs_congested_fn(void *congested_data, int bdi_bits)
1460 {
1461         struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
1462         int ret = 0;
1463         struct btrfs_device *device;
1464         struct backing_dev_info *bdi;
1465
1466         rcu_read_lock();
1467         list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
1468                 if (!device->bdev)
1469                         continue;
1470                 bdi = blk_get_backing_dev_info(device->bdev);
1471                 if (bdi && bdi_congested(bdi, bdi_bits)) {
1472                         ret = 1;
1473                         break;
1474                 }
1475         }
1476         rcu_read_unlock();
1477         return ret;
1478 }
1479
1480 /*
1481  * If this fails, caller must call bdi_destroy() to get rid of the
1482  * bdi again.
1483  */
1484 static int setup_bdi(struct btrfs_fs_info *info, struct backing_dev_info *bdi)
1485 {
1486         int err;
1487
1488         bdi->capabilities = BDI_CAP_MAP_COPY;
1489         err = bdi_setup_and_register(bdi, "btrfs", BDI_CAP_MAP_COPY);
1490         if (err)
1491                 return err;
1492
1493         bdi->ra_pages   = default_backing_dev_info.ra_pages;
1494         bdi->congested_fn       = btrfs_congested_fn;
1495         bdi->congested_data     = info;
1496         return 0;
1497 }
1498
1499 static int bio_ready_for_csum(struct bio *bio)
1500 {
1501         u64 length = 0;
1502         u64 buf_len = 0;
1503         u64 start = 0;
1504         struct page *page;
1505         struct extent_io_tree *io_tree = NULL;
1506         struct bio_vec *bvec;
1507         int i;
1508         int ret;
1509
1510         bio_for_each_segment(bvec, bio, i) {
1511                 page = bvec->bv_page;
1512                 if (page->private == EXTENT_PAGE_PRIVATE) {
1513                         length += bvec->bv_len;
1514                         continue;
1515                 }
1516                 if (!page->private) {
1517                         length += bvec->bv_len;
1518                         continue;
1519                 }
1520                 length = bvec->bv_len;
1521                 buf_len = page->private >> 2;
1522                 start = page_offset(page) + bvec->bv_offset;
1523                 io_tree = &BTRFS_I(page->mapping->host)->io_tree;
1524         }
1525         /* are we fully contained in this bio? */
1526         if (buf_len <= length)
1527                 return 1;
1528
1529         ret = extent_range_uptodate(io_tree, start + length,
1530                                     start + buf_len - 1);
1531         return ret;
1532 }
1533
1534 /*
1535  * called by the kthread helper functions to finally call the bio end_io
1536  * functions.  This is where read checksum verification actually happens
1537  */
1538 static void end_workqueue_fn(struct btrfs_work *work)
1539 {
1540         struct bio *bio;
1541         struct end_io_wq *end_io_wq;
1542         struct btrfs_fs_info *fs_info;
1543         int error;
1544
1545         end_io_wq = container_of(work, struct end_io_wq, work);
1546         bio = end_io_wq->bio;
1547         fs_info = end_io_wq->info;
1548
1549         /* metadata bio reads are special because the whole tree block must
1550          * be checksummed at once.  This makes sure the entire block is in
1551          * ram and up to date before trying to verify things.  For
1552          * blocksize <= pagesize, it is basically a noop
1553          */
1554         if (!(bio->bi_rw & REQ_WRITE) && end_io_wq->metadata &&
1555             !bio_ready_for_csum(bio)) {
1556                 btrfs_queue_worker(&fs_info->endio_meta_workers,
1557                                    &end_io_wq->work);
1558                 return;
1559         }
1560         error = end_io_wq->error;
1561         bio->bi_private = end_io_wq->private;
1562         bio->bi_end_io = end_io_wq->end_io;
1563         kfree(end_io_wq);
1564         bio_endio(bio, error);
1565 }
1566
1567 static int cleaner_kthread(void *arg)
1568 {
1569         struct btrfs_root *root = arg;
1570
1571         do {
1572                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1573
1574                 if (!(root->fs_info->sb->s_flags & MS_RDONLY) &&
1575                     mutex_trylock(&root->fs_info->cleaner_mutex)) {
1576                         btrfs_run_delayed_iputs(root);
1577                         btrfs_clean_old_snapshots(root);
1578                         mutex_unlock(&root->fs_info->cleaner_mutex);
1579                         btrfs_run_defrag_inodes(root->fs_info);
1580                 }
1581
1582                 if (freezing(current)) {
1583                         refrigerator();
1584                 } else {
1585                         set_current_state(TASK_INTERRUPTIBLE);
1586                         if (!kthread_should_stop())
1587                                 schedule();
1588                         __set_current_state(TASK_RUNNING);
1589                 }
1590         } while (!kthread_should_stop());
1591         return 0;
1592 }
1593
1594 static int transaction_kthread(void *arg)
1595 {
1596         struct btrfs_root *root = arg;
1597         struct btrfs_trans_handle *trans;
1598         struct btrfs_transaction *cur;
1599         u64 transid;
1600         unsigned long now;
1601         unsigned long delay;
1602         int ret;
1603
1604         do {
1605                 delay = HZ * 30;
1606                 vfs_check_frozen(root->fs_info->sb, SB_FREEZE_WRITE);
1607                 mutex_lock(&root->fs_info->transaction_kthread_mutex);
1608
1609                 spin_lock(&root->fs_info->trans_lock);
1610                 cur = root->fs_info->running_transaction;
1611                 if (!cur) {
1612                         spin_unlock(&root->fs_info->trans_lock);
1613                         goto sleep;
1614                 }
1615
1616                 now = get_seconds();
1617                 if (!cur->blocked &&
1618                     (now < cur->start_time || now - cur->start_time < 30)) {
1619                         spin_unlock(&root->fs_info->trans_lock);
1620                         delay = HZ * 5;
1621                         goto sleep;
1622                 }
1623                 transid = cur->transid;
1624                 spin_unlock(&root->fs_info->trans_lock);
1625
1626                 trans = btrfs_join_transaction(root);
1627                 BUG_ON(IS_ERR(trans));
1628                 if (transid == trans->transid) {
1629                         ret = btrfs_commit_transaction(trans, root);
1630                         BUG_ON(ret);
1631                 } else {
1632                         btrfs_end_transaction(trans, root);
1633                 }
1634 sleep:
1635                 wake_up_process(root->fs_info->cleaner_kthread);
1636                 mutex_unlock(&root->fs_info->transaction_kthread_mutex);
1637
1638                 if (freezing(current)) {
1639                         refrigerator();
1640                 } else {
1641                         set_current_state(TASK_INTERRUPTIBLE);
1642                         if (!kthread_should_stop() &&
1643                             !btrfs_transaction_blocked(root->fs_info))
1644                                 schedule_timeout(delay);
1645                         __set_current_state(TASK_RUNNING);
1646                 }
1647         } while (!kthread_should_stop());
1648         return 0;
1649 }
1650
1651 /*
1652  * this will find the highest generation in the array of
1653  * root backups.  The index of the highest array is returned,
1654  * or -1 if we can't find anything.
1655  *
1656  * We check to make sure the array is valid by comparing the
1657  * generation of the latest  root in the array with the generation
1658  * in the super block.  If they don't match we pitch it.
1659  */
1660 static int find_newest_super_backup(struct btrfs_fs_info *info, u64 newest_gen)
1661 {
1662         u64 cur;
1663         int newest_index = -1;
1664         struct btrfs_root_backup *root_backup;
1665         int i;
1666
1667         for (i = 0; i < BTRFS_NUM_BACKUP_ROOTS; i++) {
1668                 root_backup = info->super_copy->super_roots + i;
1669                 cur = btrfs_backup_tree_root_gen(root_backup);
1670                 if (cur == newest_gen)
1671                         newest_index = i;
1672         }
1673
1674         /* check to see if we actually wrapped around */
1675         if (newest_index == BTRFS_NUM_BACKUP_ROOTS - 1) {
1676                 root_backup = info->super_copy->super_roots;
1677                 cur = btrfs_backup_tree_root_gen(root_backup);
1678                 if (cur == newest_gen)
1679                         newest_index = 0;
1680         }
1681         return newest_index;
1682 }
1683
1684
1685 /*
1686  * find the oldest backup so we know where to store new entries
1687  * in the backup array.  This will set the backup_root_index
1688  * field in the fs_info struct
1689  */
1690 static void find_oldest_super_backup(struct btrfs_fs_info *info,
1691                                      u64 newest_gen)
1692 {
1693         int newest_index = -1;
1694
1695         newest_index = find_newest_super_backup(info, newest_gen);
1696         /* if there was garbage in there, just move along */
1697         if (newest_index == -1) {
1698                 info->backup_root_index = 0;
1699         } else {
1700                 info->backup_root_index = (newest_index + 1) % BTRFS_NUM_BACKUP_ROOTS;
1701         }
1702 }
1703
1704 /*
1705  * copy all the root pointers into the super backup array.
1706  * this will bump the backup pointer by one when it is
1707  * done
1708  */
1709 static void backup_super_roots(struct btrfs_fs_info *info)
1710 {
1711         int next_backup;
1712         struct btrfs_root_backup *root_backup;
1713         int last_backup;
1714
1715         next_backup = info->backup_root_index;
1716         last_backup = (next_backup + BTRFS_NUM_BACKUP_ROOTS - 1) %
1717                 BTRFS_NUM_BACKUP_ROOTS;
1718
1719         /*
1720          * just overwrite the last backup if we're at the same generation
1721          * this happens only at umount
1722          */
1723         root_backup = info->super_for_commit->super_roots + last_backup;
1724         if (btrfs_backup_tree_root_gen(root_backup) ==
1725             btrfs_header_generation(info->tree_root->node))
1726                 next_backup = last_backup;
1727
1728         root_backup = info->super_for_commit->super_roots + next_backup;
1729
1730         /*
1731          * make sure all of our padding and empty slots get zero filled
1732          * regardless of which ones we use today
1733          */
1734         memset(root_backup, 0, sizeof(*root_backup));
1735
1736         info->backup_root_index = (next_backup + 1) % BTRFS_NUM_BACKUP_ROOTS;
1737
1738         btrfs_set_backup_tree_root(root_backup, info->tree_root->node->start);
1739         btrfs_set_backup_tree_root_gen(root_backup,
1740                                btrfs_header_generation(info->tree_root->node));
1741
1742         btrfs_set_backup_tree_root_level(root_backup,
1743                                btrfs_header_level(info->tree_root->node));
1744
1745         btrfs_set_backup_chunk_root(root_backup, info->chunk_root->node->start);
1746         btrfs_set_backup_chunk_root_gen(root_backup,
1747                                btrfs_header_generation(info->chunk_root->node));
1748         btrfs_set_backup_chunk_root_level(root_backup,
1749                                btrfs_header_level(info->chunk_root->node));
1750
1751         btrfs_set_backup_extent_root(root_backup, info->extent_root->node->start);
1752         btrfs_set_backup_extent_root_gen(root_backup,
1753                                btrfs_header_generation(info->extent_root->node));
1754         btrfs_set_backup_extent_root_level(root_backup,
1755                                btrfs_header_level(info->extent_root->node));
1756
1757         /*
1758          * we might commit during log recovery, which happens before we set
1759          * the fs_root.  Make sure it is valid before we fill it in.
1760          */
1761         if (info->fs_root && info->fs_root->node) {
1762                 btrfs_set_backup_fs_root(root_backup,
1763                                          info->fs_root->node->start);
1764                 btrfs_set_backup_fs_root_gen(root_backup,
1765                                btrfs_header_generation(info->fs_root->node));
1766                 btrfs_set_backup_fs_root_level(root_backup,
1767                                btrfs_header_level(info->fs_root->node));
1768         }
1769
1770         btrfs_set_backup_dev_root(root_backup, info->dev_root->node->start);
1771         btrfs_set_backup_dev_root_gen(root_backup,
1772                                btrfs_header_generation(info->dev_root->node));
1773         btrfs_set_backup_dev_root_level(root_backup,
1774                                        btrfs_header_level(info->dev_root->node));
1775
1776         btrfs_set_backup_csum_root(root_backup, info->csum_root->node->start);
1777         btrfs_set_backup_csum_root_gen(root_backup,
1778                                btrfs_header_generation(info->csum_root->node));
1779         btrfs_set_backup_csum_root_level(root_backup,
1780                                btrfs_header_level(info->csum_root->node));
1781
1782         btrfs_set_backup_total_bytes(root_backup,
1783                              btrfs_super_total_bytes(info->super_copy));
1784         btrfs_set_backup_bytes_used(root_backup,
1785                              btrfs_super_bytes_used(info->super_copy));
1786         btrfs_set_backup_num_devices(root_backup,
1787                              btrfs_super_num_devices(info->super_copy));
1788
1789         /*
1790          * if we don't copy this out to the super_copy, it won't get remembered
1791          * for the next commit
1792          */
1793         memcpy(&info->super_copy->super_roots,
1794                &info->super_for_commit->super_roots,
1795                sizeof(*root_backup) * BTRFS_NUM_BACKUP_ROOTS);
1796 }
1797
1798 /*
1799  * this copies info out of the root backup array and back into
1800  * the in-memory super block.  It is meant to help iterate through
1801  * the array, so you send it the number of backups you've already
1802  * tried and the last backup index you used.
1803  *
1804  * this returns -1 when it has tried all the backups
1805  */
1806 static noinline int next_root_backup(struct btrfs_fs_info *info,
1807                                      struct btrfs_super_block *super,
1808                                      int *num_backups_tried, int *backup_index)
1809 {
1810         struct btrfs_root_backup *root_backup;
1811         int newest = *backup_index;
1812
1813         if (*num_backups_tried == 0) {
1814                 u64 gen = btrfs_super_generation(super);
1815
1816                 newest = find_newest_super_backup(info, gen);
1817                 if (newest == -1)
1818                         return -1;
1819
1820                 *backup_index = newest;
1821                 *num_backups_tried = 1;
1822         } else if (*num_backups_tried == BTRFS_NUM_BACKUP_ROOTS) {
1823                 /* we've tried all the backups, all done */
1824                 return -1;
1825         } else {
1826                 /* jump to the next oldest backup */
1827                 newest = (*backup_index + BTRFS_NUM_BACKUP_ROOTS - 1) %
1828                         BTRFS_NUM_BACKUP_ROOTS;
1829                 *backup_index = newest;
1830                 *num_backups_tried += 1;
1831         }
1832         root_backup = super->super_roots + newest;
1833
1834         btrfs_set_super_generation(super,
1835                                    btrfs_backup_tree_root_gen(root_backup));
1836         btrfs_set_super_root(super, btrfs_backup_tree_root(root_backup));
1837         btrfs_set_super_root_level(super,
1838                                    btrfs_backup_tree_root_level(root_backup));
1839         btrfs_set_super_bytes_used(super, btrfs_backup_bytes_used(root_backup));
1840
1841         /*
1842          * fixme: the total bytes and num_devices need to match or we should
1843          * need a fsck
1844          */
1845         btrfs_set_super_total_bytes(super, btrfs_backup_total_bytes(root_backup));
1846         btrfs_set_super_num_devices(super, btrfs_backup_num_devices(root_backup));
1847         return 0;
1848 }
1849
1850 /* helper to cleanup tree roots */
1851 static void free_root_pointers(struct btrfs_fs_info *info, int chunk_root)
1852 {
1853         free_extent_buffer(info->tree_root->node);
1854         free_extent_buffer(info->tree_root->commit_root);
1855         free_extent_buffer(info->dev_root->node);
1856         free_extent_buffer(info->dev_root->commit_root);
1857         free_extent_buffer(info->extent_root->node);
1858         free_extent_buffer(info->extent_root->commit_root);
1859         free_extent_buffer(info->csum_root->node);
1860         free_extent_buffer(info->csum_root->commit_root);
1861
1862         info->tree_root->node = NULL;
1863         info->tree_root->commit_root = NULL;
1864         info->dev_root->node = NULL;
1865         info->dev_root->commit_root = NULL;
1866         info->extent_root->node = NULL;
1867         info->extent_root->commit_root = NULL;
1868         info->csum_root->node = NULL;
1869         info->csum_root->commit_root = NULL;
1870
1871         if (chunk_root) {
1872                 free_extent_buffer(info->chunk_root->node);
1873                 free_extent_buffer(info->chunk_root->commit_root);
1874                 info->chunk_root->node = NULL;
1875                 info->chunk_root->commit_root = NULL;
1876         }
1877 }
1878
1879
1880 struct btrfs_root *open_ctree(struct super_block *sb,
1881                               struct btrfs_fs_devices *fs_devices,
1882                               char *options)
1883 {
1884         u32 sectorsize;
1885         u32 nodesize;
1886         u32 leafsize;
1887         u32 blocksize;
1888         u32 stripesize;
1889         u64 generation;
1890         u64 features;
1891         struct btrfs_key location;
1892         struct buffer_head *bh;
1893         struct btrfs_super_block *disk_super;
1894         struct btrfs_root *tree_root = btrfs_sb(sb);
1895         struct btrfs_fs_info *fs_info = tree_root->fs_info;
1896         struct btrfs_root *extent_root;
1897         struct btrfs_root *csum_root;
1898         struct btrfs_root *chunk_root;
1899         struct btrfs_root *dev_root;
1900         struct btrfs_root *log_tree_root;
1901         int ret;
1902         int err = -EINVAL;
1903         int num_backups_tried = 0;
1904         int backup_index = 0;
1905
1906         extent_root = fs_info->extent_root =
1907                 kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1908         csum_root = fs_info->csum_root =
1909                 kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1910         chunk_root = fs_info->chunk_root =
1911                 kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1912         dev_root = fs_info->dev_root =
1913                 kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
1914
1915         if (!extent_root || !csum_root || !chunk_root || !dev_root) {
1916                 err = -ENOMEM;
1917                 goto fail;
1918         }
1919
1920         ret = init_srcu_struct(&fs_info->subvol_srcu);
1921         if (ret) {
1922                 err = ret;
1923                 goto fail;
1924         }
1925
1926         ret = setup_bdi(fs_info, &fs_info->bdi);
1927         if (ret) {
1928                 err = ret;
1929                 goto fail_srcu;
1930         }
1931
1932         fs_info->btree_inode = new_inode(sb);
1933         if (!fs_info->btree_inode) {
1934                 err = -ENOMEM;
1935                 goto fail_bdi;
1936         }
1937
1938         mapping_set_gfp_mask(fs_info->btree_inode->i_mapping, GFP_NOFS);
1939
1940         INIT_RADIX_TREE(&fs_info->fs_roots_radix, GFP_ATOMIC);
1941         INIT_LIST_HEAD(&fs_info->trans_list);
1942         INIT_LIST_HEAD(&fs_info->dead_roots);
1943         INIT_LIST_HEAD(&fs_info->delayed_iputs);
1944         INIT_LIST_HEAD(&fs_info->hashers);
1945         INIT_LIST_HEAD(&fs_info->delalloc_inodes);
1946         INIT_LIST_HEAD(&fs_info->ordered_operations);
1947         INIT_LIST_HEAD(&fs_info->caching_block_groups);
1948         spin_lock_init(&fs_info->delalloc_lock);
1949         spin_lock_init(&fs_info->trans_lock);
1950         spin_lock_init(&fs_info->ref_cache_lock);
1951         spin_lock_init(&fs_info->fs_roots_radix_lock);
1952         spin_lock_init(&fs_info->delayed_iput_lock);
1953         spin_lock_init(&fs_info->defrag_inodes_lock);
1954         spin_lock_init(&fs_info->free_chunk_lock);
1955         mutex_init(&fs_info->reloc_mutex);
1956
1957         init_completion(&fs_info->kobj_unregister);
1958         INIT_LIST_HEAD(&fs_info->dirty_cowonly_roots);
1959         INIT_LIST_HEAD(&fs_info->space_info);
1960         btrfs_mapping_init(&fs_info->mapping_tree);
1961         btrfs_init_block_rsv(&fs_info->global_block_rsv);
1962         btrfs_init_block_rsv(&fs_info->delalloc_block_rsv);
1963         btrfs_init_block_rsv(&fs_info->trans_block_rsv);
1964         btrfs_init_block_rsv(&fs_info->chunk_block_rsv);
1965         btrfs_init_block_rsv(&fs_info->empty_block_rsv);
1966         btrfs_init_block_rsv(&fs_info->delayed_block_rsv);
1967         atomic_set(&fs_info->nr_async_submits, 0);
1968         atomic_set(&fs_info->async_delalloc_pages, 0);
1969         atomic_set(&fs_info->async_submit_draining, 0);
1970         atomic_set(&fs_info->nr_async_bios, 0);
1971         atomic_set(&fs_info->defrag_running, 0);
1972         fs_info->sb = sb;
1973         fs_info->max_inline = 8192 * 1024;
1974         fs_info->metadata_ratio = 0;
1975         fs_info->defrag_inodes = RB_ROOT;
1976         fs_info->trans_no_join = 0;
1977         fs_info->free_chunk_space = 0;
1978
1979         /* readahead state */
1980         INIT_RADIX_TREE(&fs_info->reada_tree, GFP_NOFS & ~__GFP_WAIT);
1981         spin_lock_init(&fs_info->reada_lock);
1982
1983         fs_info->thread_pool_size = min_t(unsigned long,
1984                                           num_online_cpus() + 2, 8);
1985
1986         INIT_LIST_HEAD(&fs_info->ordered_extents);
1987         spin_lock_init(&fs_info->ordered_extent_lock);
1988         fs_info->delayed_root = kmalloc(sizeof(struct btrfs_delayed_root),
1989                                         GFP_NOFS);
1990         if (!fs_info->delayed_root) {
1991                 err = -ENOMEM;
1992                 goto fail_iput;
1993         }
1994         btrfs_init_delayed_root(fs_info->delayed_root);
1995
1996         mutex_init(&fs_info->scrub_lock);
1997         atomic_set(&fs_info->scrubs_running, 0);
1998         atomic_set(&fs_info->scrub_pause_req, 0);
1999         atomic_set(&fs_info->scrubs_paused, 0);
2000         atomic_set(&fs_info->scrub_cancel_req, 0);
2001         init_waitqueue_head(&fs_info->scrub_pause_wait);
2002         init_rwsem(&fs_info->scrub_super_lock);
2003         fs_info->scrub_workers_refcnt = 0;
2004
2005         spin_lock_init(&fs_info->balance_lock);
2006         mutex_init(&fs_info->balance_mutex);
2007         atomic_set(&fs_info->balance_running, 0);
2008         atomic_set(&fs_info->balance_pause_req, 0);
2009         atomic_set(&fs_info->balance_cancel_req, 0);
2010         fs_info->balance_ctl = NULL;
2011         init_waitqueue_head(&fs_info->balance_wait_q);
2012
2013         sb->s_blocksize = 4096;
2014         sb->s_blocksize_bits = blksize_bits(4096);
2015         sb->s_bdi = &fs_info->bdi;
2016
2017         fs_info->btree_inode->i_ino = BTRFS_BTREE_INODE_OBJECTID;
2018         set_nlink(fs_info->btree_inode, 1);
2019         /*
2020          * we set the i_size on the btree inode to the max possible int.
2021          * the real end of the address space is determined by all of
2022          * the devices in the system
2023          */
2024         fs_info->btree_inode->i_size = OFFSET_MAX;
2025         fs_info->btree_inode->i_mapping->a_ops = &btree_aops;
2026         fs_info->btree_inode->i_mapping->backing_dev_info = &fs_info->bdi;
2027
2028         RB_CLEAR_NODE(&BTRFS_I(fs_info->btree_inode)->rb_node);
2029         extent_io_tree_init(&BTRFS_I(fs_info->btree_inode)->io_tree,
2030                              fs_info->btree_inode->i_mapping);
2031         extent_map_tree_init(&BTRFS_I(fs_info->btree_inode)->extent_tree);
2032
2033         BTRFS_I(fs_info->btree_inode)->io_tree.ops = &btree_extent_io_ops;
2034
2035         BTRFS_I(fs_info->btree_inode)->root = tree_root;
2036         memset(&BTRFS_I(fs_info->btree_inode)->location, 0,
2037                sizeof(struct btrfs_key));
2038         BTRFS_I(fs_info->btree_inode)->dummy_inode = 1;
2039         insert_inode_hash(fs_info->btree_inode);
2040
2041         spin_lock_init(&fs_info->block_group_cache_lock);
2042         fs_info->block_group_cache_tree = RB_ROOT;
2043
2044         extent_io_tree_init(&fs_info->freed_extents[0],
2045                              fs_info->btree_inode->i_mapping);
2046         extent_io_tree_init(&fs_info->freed_extents[1],
2047                              fs_info->btree_inode->i_mapping);
2048         fs_info->pinned_extents = &fs_info->freed_extents[0];
2049         fs_info->do_barriers = 1;
2050
2051
2052         mutex_init(&fs_info->ordered_operations_mutex);
2053         mutex_init(&fs_info->tree_log_mutex);
2054         mutex_init(&fs_info->chunk_mutex);
2055         mutex_init(&fs_info->transaction_kthread_mutex);
2056         mutex_init(&fs_info->cleaner_mutex);
2057         mutex_init(&fs_info->volume_mutex);
2058         init_rwsem(&fs_info->extent_commit_sem);
2059         init_rwsem(&fs_info->cleanup_work_sem);
2060         init_rwsem(&fs_info->subvol_sem);
2061
2062         btrfs_init_free_cluster(&fs_info->meta_alloc_cluster);
2063         btrfs_init_free_cluster(&fs_info->data_alloc_cluster);
2064
2065         init_waitqueue_head(&fs_info->transaction_throttle);
2066         init_waitqueue_head(&fs_info->transaction_wait);
2067         init_waitqueue_head(&fs_info->transaction_blocked_wait);
2068         init_waitqueue_head(&fs_info->async_submit_wait);
2069
2070         __setup_root(4096, 4096, 4096, 4096, tree_root,
2071                      fs_info, BTRFS_ROOT_TREE_OBJECTID);
2072
2073         bh = btrfs_read_dev_super(fs_devices->latest_bdev);
2074         if (!bh) {
2075                 err = -EINVAL;
2076                 goto fail_alloc;
2077         }
2078
2079         memcpy(fs_info->super_copy, bh->b_data, sizeof(*fs_info->super_copy));
2080         memcpy(fs_info->super_for_commit, fs_info->super_copy,
2081                sizeof(*fs_info->super_for_commit));
2082         brelse(bh);
2083
2084         memcpy(fs_info->fsid, fs_info->super_copy->fsid, BTRFS_FSID_SIZE);
2085
2086         disk_super = fs_info->super_copy;
2087         if (!btrfs_super_root(disk_super))
2088                 goto fail_alloc;
2089
2090         /* check FS state, whether FS is broken. */
2091         fs_info->fs_state |= btrfs_super_flags(disk_super);
2092
2093         btrfs_check_super_valid(fs_info, sb->s_flags & MS_RDONLY);
2094
2095         /*
2096          * run through our array of backup supers and setup
2097          * our ring pointer to the oldest one
2098          */
2099         generation = btrfs_super_generation(disk_super);
2100         find_oldest_super_backup(fs_info, generation);
2101
2102         /*
2103          * In the long term, we'll store the compression type in the super
2104          * block, and it'll be used for per file compression control.
2105          */
2106         fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
2107
2108         ret = btrfs_parse_options(tree_root, options);
2109         if (ret) {
2110                 err = ret;
2111                 goto fail_alloc;
2112         }
2113
2114         features = btrfs_super_incompat_flags(disk_super) &
2115                 ~BTRFS_FEATURE_INCOMPAT_SUPP;
2116         if (features) {
2117                 printk(KERN_ERR "BTRFS: couldn't mount because of "
2118                        "unsupported optional features (%Lx).\n",
2119                        (unsigned long long)features);
2120                 err = -EINVAL;
2121                 goto fail_alloc;
2122         }
2123
2124         features = btrfs_super_incompat_flags(disk_super);
2125         features |= BTRFS_FEATURE_INCOMPAT_MIXED_BACKREF;
2126         if (tree_root->fs_info->compress_type & BTRFS_COMPRESS_LZO)
2127                 features |= BTRFS_FEATURE_INCOMPAT_COMPRESS_LZO;
2128         btrfs_set_super_incompat_flags(disk_super, features);
2129
2130         features = btrfs_super_compat_ro_flags(disk_super) &
2131                 ~BTRFS_FEATURE_COMPAT_RO_SUPP;
2132         if (!(sb->s_flags & MS_RDONLY) && features) {
2133                 printk(KERN_ERR "BTRFS: couldn't mount RDWR because of "
2134                        "unsupported option features (%Lx).\n",
2135                        (unsigned long long)features);
2136                 err = -EINVAL;
2137                 goto fail_alloc;
2138         }
2139
2140         btrfs_init_workers(&fs_info->generic_worker,
2141                            "genwork", 1, NULL);
2142
2143         btrfs_init_workers(&fs_info->workers, "worker",
2144                            fs_info->thread_pool_size,
2145                            &fs_info->generic_worker);
2146
2147         btrfs_init_workers(&fs_info->delalloc_workers, "delalloc",
2148                            fs_info->thread_pool_size,
2149                            &fs_info->generic_worker);
2150
2151         btrfs_init_workers(&fs_info->submit_workers, "submit",
2152                            min_t(u64, fs_devices->num_devices,
2153                            fs_info->thread_pool_size),
2154                            &fs_info->generic_worker);
2155
2156         btrfs_init_workers(&fs_info->caching_workers, "cache",
2157                            2, &fs_info->generic_worker);
2158
2159         /* a higher idle thresh on the submit workers makes it much more
2160          * likely that bios will be send down in a sane order to the
2161          * devices
2162          */
2163         fs_info->submit_workers.idle_thresh = 64;
2164
2165         fs_info->workers.idle_thresh = 16;
2166         fs_info->workers.ordered = 1;
2167
2168         fs_info->delalloc_workers.idle_thresh = 2;
2169         fs_info->delalloc_workers.ordered = 1;
2170
2171         btrfs_init_workers(&fs_info->fixup_workers, "fixup", 1,
2172                            &fs_info->generic_worker);
2173         btrfs_init_workers(&fs_info->endio_workers, "endio",
2174                            fs_info->thread_pool_size,
2175                            &fs_info->generic_worker);
2176         btrfs_init_workers(&fs_info->endio_meta_workers, "endio-meta",
2177                            fs_info->thread_pool_size,
2178                            &fs_info->generic_worker);
2179         btrfs_init_workers(&fs_info->endio_meta_write_workers,
2180                            "endio-meta-write", fs_info->thread_pool_size,
2181                            &fs_info->generic_worker);
2182         btrfs_init_workers(&fs_info->endio_write_workers, "endio-write",
2183                            fs_info->thread_pool_size,
2184                            &fs_info->generic_worker);
2185         btrfs_init_workers(&fs_info->endio_freespace_worker, "freespace-write",
2186                            1, &fs_info->generic_worker);
2187         btrfs_init_workers(&fs_info->delayed_workers, "delayed-meta",
2188                            fs_info->thread_pool_size,
2189                            &fs_info->generic_worker);
2190         btrfs_init_workers(&fs_info->readahead_workers, "readahead",
2191                            fs_info->thread_pool_size,
2192                            &fs_info->generic_worker);
2193
2194         /*
2195          * endios are largely parallel and should have a very
2196          * low idle thresh
2197          */
2198         fs_info->endio_workers.idle_thresh = 4;
2199         fs_info->endio_meta_workers.idle_thresh = 4;
2200
2201         fs_info->endio_write_workers.idle_thresh = 2;
2202         fs_info->endio_meta_write_workers.idle_thresh = 2;
2203         fs_info->readahead_workers.idle_thresh = 2;
2204
2205         /*
2206          * btrfs_start_workers can really only fail because of ENOMEM so just
2207          * return -ENOMEM if any of these fail.
2208          */
2209         ret = btrfs_start_workers(&fs_info->workers);
2210         ret |= btrfs_start_workers(&fs_info->generic_worker);
2211         ret |= btrfs_start_workers(&fs_info->submit_workers);
2212         ret |= btrfs_start_workers(&fs_info->delalloc_workers);
2213         ret |= btrfs_start_workers(&fs_info->fixup_workers);
2214         ret |= btrfs_start_workers(&fs_info->endio_workers);
2215         ret |= btrfs_start_workers(&fs_info->endio_meta_workers);
2216         ret |= btrfs_start_workers(&fs_info->endio_meta_write_workers);
2217         ret |= btrfs_start_workers(&fs_info->endio_write_workers);
2218         ret |= btrfs_start_workers(&fs_info->endio_freespace_worker);
2219         ret |= btrfs_start_workers(&fs_info->delayed_workers);
2220         ret |= btrfs_start_workers(&fs_info->caching_workers);
2221         ret |= btrfs_start_workers(&fs_info->readahead_workers);
2222         if (ret) {
2223                 ret = -ENOMEM;
2224                 goto fail_sb_buffer;
2225         }
2226
2227         fs_info->bdi.ra_pages *= btrfs_super_num_devices(disk_super);
2228         fs_info->bdi.ra_pages = max(fs_info->bdi.ra_pages,
2229                                     4 * 1024 * 1024 / PAGE_CACHE_SIZE);
2230
2231         nodesize = btrfs_super_nodesize(disk_super);
2232         leafsize = btrfs_super_leafsize(disk_super);
2233         sectorsize = btrfs_super_sectorsize(disk_super);
2234         stripesize = btrfs_super_stripesize(disk_super);
2235         tree_root->nodesize = nodesize;
2236         tree_root->leafsize = leafsize;
2237         tree_root->sectorsize = sectorsize;
2238         tree_root->stripesize = stripesize;
2239
2240         sb->s_blocksize = sectorsize;
2241         sb->s_blocksize_bits = blksize_bits(sectorsize);
2242
2243         if (strncmp((char *)(&disk_super->magic), BTRFS_MAGIC,
2244                     sizeof(disk_super->magic))) {
2245                 printk(KERN_INFO "btrfs: valid FS not found on %s\n", sb->s_id);
2246                 goto fail_sb_buffer;
2247         }
2248
2249         mutex_lock(&fs_info->chunk_mutex);
2250         ret = btrfs_read_sys_array(tree_root);
2251         mutex_unlock(&fs_info->chunk_mutex);
2252         if (ret) {
2253                 printk(KERN_WARNING "btrfs: failed to read the system "
2254                        "array on %s\n", sb->s_id);
2255                 goto fail_sb_buffer;
2256         }
2257
2258         blocksize = btrfs_level_size(tree_root,
2259                                      btrfs_super_chunk_root_level(disk_super));
2260         generation = btrfs_super_chunk_root_generation(disk_super);
2261
2262         __setup_root(nodesize, leafsize, sectorsize, stripesize,
2263                      chunk_root, fs_info, BTRFS_CHUNK_TREE_OBJECTID);
2264
2265         chunk_root->node = read_tree_block(chunk_root,
2266                                            btrfs_super_chunk_root(disk_super),
2267                                            blocksize, generation);
2268         BUG_ON(!chunk_root->node);
2269         if (!test_bit(EXTENT_BUFFER_UPTODATE, &chunk_root->node->bflags)) {
2270                 printk(KERN_WARNING "btrfs: failed to read chunk root on %s\n",
2271                        sb->s_id);
2272                 goto fail_tree_roots;
2273         }
2274         btrfs_set_root_node(&chunk_root->root_item, chunk_root->node);
2275         chunk_root->commit_root = btrfs_root_node(chunk_root);
2276
2277         read_extent_buffer(chunk_root->node, fs_info->chunk_tree_uuid,
2278            (unsigned long)btrfs_header_chunk_tree_uuid(chunk_root->node),
2279            BTRFS_UUID_SIZE);
2280
2281         ret = btrfs_read_chunk_tree(chunk_root);
2282         if (ret) {
2283                 printk(KERN_WARNING "btrfs: failed to read chunk tree on %s\n",
2284                        sb->s_id);
2285                 goto fail_tree_roots;
2286         }
2287
2288         btrfs_close_extra_devices(fs_devices);
2289
2290 retry_root_backup:
2291         blocksize = btrfs_level_size(tree_root,
2292                                      btrfs_super_root_level(disk_super));
2293         generation = btrfs_super_generation(disk_super);
2294
2295         tree_root->node = read_tree_block(tree_root,
2296                                           btrfs_super_root(disk_super),
2297                                           blocksize, generation);
2298         if (!tree_root->node ||
2299             !test_bit(EXTENT_BUFFER_UPTODATE, &tree_root->node->bflags)) {
2300                 printk(KERN_WARNING "btrfs: failed to read tree root on %s\n",
2301                        sb->s_id);
2302
2303                 goto recovery_tree_root;
2304         }
2305
2306         btrfs_set_root_node(&tree_root->root_item, tree_root->node);
2307         tree_root->commit_root = btrfs_root_node(tree_root);
2308
2309         ret = find_and_setup_root(tree_root, fs_info,
2310                                   BTRFS_EXTENT_TREE_OBJECTID, extent_root);
2311         if (ret)
2312                 goto recovery_tree_root;
2313         extent_root->track_dirty = 1;
2314
2315         ret = find_and_setup_root(tree_root, fs_info,
2316                                   BTRFS_DEV_TREE_OBJECTID, dev_root);
2317         if (ret)
2318                 goto recovery_tree_root;
2319         dev_root->track_dirty = 1;
2320
2321         ret = find_and_setup_root(tree_root, fs_info,
2322                                   BTRFS_CSUM_TREE_OBJECTID, csum_root);
2323         if (ret)
2324                 goto recovery_tree_root;
2325
2326         csum_root->track_dirty = 1;
2327
2328         fs_info->generation = generation;
2329         fs_info->last_trans_committed = generation;
2330
2331         ret = btrfs_init_space_info(fs_info);
2332         if (ret) {
2333                 printk(KERN_ERR "Failed to initial space info: %d\n", ret);
2334                 goto fail_block_groups;
2335         }
2336
2337         ret = btrfs_read_block_groups(extent_root);
2338         if (ret) {
2339                 printk(KERN_ERR "Failed to read block groups: %d\n", ret);
2340                 goto fail_block_groups;
2341         }
2342
2343         fs_info->cleaner_kthread = kthread_run(cleaner_kthread, tree_root,
2344                                                "btrfs-cleaner");
2345         if (IS_ERR(fs_info->cleaner_kthread))
2346                 goto fail_block_groups;
2347
2348         fs_info->transaction_kthread = kthread_run(transaction_kthread,
2349                                                    tree_root,
2350                                                    "btrfs-transaction");
2351         if (IS_ERR(fs_info->transaction_kthread))
2352                 goto fail_cleaner;
2353
2354         if (!btrfs_test_opt(tree_root, SSD) &&
2355             !btrfs_test_opt(tree_root, NOSSD) &&
2356             !fs_info->fs_devices->rotating) {
2357                 printk(KERN_INFO "Btrfs detected SSD devices, enabling SSD "
2358                        "mode\n");
2359                 btrfs_set_opt(fs_info->mount_opt, SSD);
2360         }
2361
2362         /* do not make disk changes in broken FS */
2363         if (btrfs_super_log_root(disk_super) != 0 &&
2364             !(fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)) {
2365                 u64 bytenr = btrfs_super_log_root(disk_super);
2366
2367                 if (fs_devices->rw_devices == 0) {
2368                         printk(KERN_WARNING "Btrfs log replay required "
2369                                "on RO media\n");
2370                         err = -EIO;
2371                         goto fail_trans_kthread;
2372                 }
2373                 blocksize =
2374                      btrfs_level_size(tree_root,
2375                                       btrfs_super_log_root_level(disk_super));
2376
2377                 log_tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS);
2378                 if (!log_tree_root) {
2379                         err = -ENOMEM;
2380                         goto fail_trans_kthread;
2381                 }
2382
2383                 __setup_root(nodesize, leafsize, sectorsize, stripesize,
2384                              log_tree_root, fs_info, BTRFS_TREE_LOG_OBJECTID);
2385
2386                 log_tree_root->node = read_tree_block(tree_root, bytenr,
2387                                                       blocksize,
2388                                                       generation + 1);
2389                 ret = btrfs_recover_log_trees(log_tree_root);
2390                 BUG_ON(ret);
2391
2392                 if (sb->s_flags & MS_RDONLY) {
2393                         ret =  btrfs_commit_super(tree_root);
2394                         BUG_ON(ret);
2395                 }
2396         }
2397
2398         ret = btrfs_find_orphan_roots(tree_root);
2399         BUG_ON(ret);
2400
2401         if (!(sb->s_flags & MS_RDONLY)) {
2402                 ret = btrfs_cleanup_fs_roots(fs_info);
2403                 BUG_ON(ret);
2404
2405                 ret = btrfs_recover_relocation(tree_root);
2406                 if (ret < 0) {
2407                         printk(KERN_WARNING
2408                                "btrfs: failed to recover relocation\n");
2409                         err = -EINVAL;
2410                         goto fail_trans_kthread;
2411                 }
2412         }
2413
2414         location.objectid = BTRFS_FS_TREE_OBJECTID;
2415         location.type = BTRFS_ROOT_ITEM_KEY;
2416         location.offset = (u64)-1;
2417
2418         fs_info->fs_root = btrfs_read_fs_root_no_name(fs_info, &location);
2419         if (!fs_info->fs_root)
2420                 goto fail_trans_kthread;
2421         if (IS_ERR(fs_info->fs_root)) {
2422                 err = PTR_ERR(fs_info->fs_root);
2423                 goto fail_trans_kthread;
2424         }
2425
2426         if (!(sb->s_flags & MS_RDONLY)) {
2427                 down_read(&fs_info->cleanup_work_sem);
2428                 err = btrfs_orphan_cleanup(fs_info->fs_root);
2429                 if (!err)
2430                         err = btrfs_orphan_cleanup(fs_info->tree_root);
2431                 up_read(&fs_info->cleanup_work_sem);
2432
2433                 if (!err)
2434                         err = btrfs_recover_balance(fs_info->tree_root);
2435
2436                 if (err) {
2437                         close_ctree(tree_root);
2438                         return ERR_PTR(err);
2439                 }
2440         }
2441
2442         return tree_root;
2443
2444 fail_trans_kthread:
2445         kthread_stop(fs_info->transaction_kthread);
2446 fail_cleaner:
2447         kthread_stop(fs_info->cleaner_kthread);
2448
2449         /*
2450          * make sure we're done with the btree inode before we stop our
2451          * kthreads
2452          */
2453         filemap_write_and_wait(fs_info->btree_inode->i_mapping);
2454         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2455
2456 fail_block_groups:
2457         btrfs_free_block_groups(fs_info);
2458
2459 fail_tree_roots:
2460         free_root_pointers(fs_info, 1);
2461
2462 fail_sb_buffer:
2463         btrfs_stop_workers(&fs_info->generic_worker);
2464         btrfs_stop_workers(&fs_info->readahead_workers);
2465         btrfs_stop_workers(&fs_info->fixup_workers);
2466         btrfs_stop_workers(&fs_info->delalloc_workers);
2467         btrfs_stop_workers(&fs_info->workers);
2468         btrfs_stop_workers(&fs_info->endio_workers);
2469         btrfs_stop_workers(&fs_info->endio_meta_workers);
2470         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
2471         btrfs_stop_workers(&fs_info->endio_write_workers);
2472         btrfs_stop_workers(&fs_info->endio_freespace_worker);
2473         btrfs_stop_workers(&fs_info->submit_workers);
2474         btrfs_stop_workers(&fs_info->delayed_workers);
2475         btrfs_stop_workers(&fs_info->caching_workers);
2476 fail_alloc:
2477 fail_iput:
2478         btrfs_mapping_tree_free(&fs_info->mapping_tree);
2479
2480         invalidate_inode_pages2(fs_info->btree_inode->i_mapping);
2481         iput(fs_info->btree_inode);
2482 fail_bdi:
2483         bdi_destroy(&fs_info->bdi);
2484 fail_srcu:
2485         cleanup_srcu_struct(&fs_info->subvol_srcu);
2486 fail:
2487         btrfs_close_devices(fs_info->fs_devices);
2488         free_fs_info(fs_info);
2489         return ERR_PTR(err);
2490
2491 recovery_tree_root:
2492         if (!btrfs_test_opt(tree_root, RECOVERY))
2493                 goto fail_tree_roots;
2494
2495         free_root_pointers(fs_info, 0);
2496
2497         /* don't use the log in recovery mode, it won't be valid */
2498         btrfs_set_super_log_root(disk_super, 0);
2499
2500         /* we can't trust the free space cache either */
2501         btrfs_set_opt(fs_info->mount_opt, CLEAR_CACHE);
2502
2503         ret = next_root_backup(fs_info, fs_info->super_copy,
2504                                &num_backups_tried, &backup_index);
2505         if (ret == -1)
2506                 goto fail_block_groups;
2507         goto retry_root_backup;
2508 }
2509
2510 static void btrfs_end_buffer_write_sync(struct buffer_head *bh, int uptodate)
2511 {
2512         char b[BDEVNAME_SIZE];
2513
2514         if (uptodate) {
2515                 set_buffer_uptodate(bh);
2516         } else {
2517                 printk_ratelimited(KERN_WARNING "lost page write due to "
2518                                         "I/O error on %s\n",
2519                                        bdevname(bh->b_bdev, b));
2520                 /* note, we dont' set_buffer_write_io_error because we have
2521                  * our own ways of dealing with the IO errors
2522                  */
2523                 clear_buffer_uptodate(bh);
2524         }
2525         unlock_buffer(bh);
2526         put_bh(bh);
2527 }
2528
2529 struct buffer_head *btrfs_read_dev_super(struct block_device *bdev)
2530 {
2531         struct buffer_head *bh;
2532         struct buffer_head *latest = NULL;
2533         struct btrfs_super_block *super;
2534         int i;
2535         u64 transid = 0;
2536         u64 bytenr;
2537
2538         /* we would like to check all the supers, but that would make
2539          * a btrfs mount succeed after a mkfs from a different FS.
2540          * So, we need to add a special mount option to scan for
2541          * later supers, using BTRFS_SUPER_MIRROR_MAX instead
2542          */
2543         for (i = 0; i < 1; i++) {
2544                 bytenr = btrfs_sb_offset(i);
2545                 if (bytenr + 4096 >= i_size_read(bdev->bd_inode))
2546                         break;
2547                 bh = __bread(bdev, bytenr / 4096, 4096);
2548                 if (!bh)
2549                         continue;
2550
2551                 super = (struct btrfs_super_block *)bh->b_data;
2552                 if (btrfs_super_bytenr(super) != bytenr ||
2553                     strncmp((char *)(&super->magic), BTRFS_MAGIC,
2554                             sizeof(super->magic))) {
2555                         brelse(bh);
2556                         continue;
2557                 }
2558
2559                 if (!latest || btrfs_super_generation(super) > transid) {
2560                         brelse(latest);
2561                         latest = bh;
2562                         transid = btrfs_super_generation(super);
2563                 } else {
2564                         brelse(bh);
2565                 }
2566         }
2567         return latest;
2568 }
2569
2570 /*
2571  * this should be called twice, once with wait == 0 and
2572  * once with wait == 1.  When wait == 0 is done, all the buffer heads
2573  * we write are pinned.
2574  *
2575  * They are released when wait == 1 is done.
2576  * max_mirrors must be the same for both runs, and it indicates how
2577  * many supers on this one device should be written.
2578  *
2579  * max_mirrors == 0 means to write them all.
2580  */
2581 static int write_dev_supers(struct btrfs_device *device,
2582                             struct btrfs_super_block *sb,
2583                             int do_barriers, int wait, int max_mirrors)
2584 {
2585         struct buffer_head *bh;
2586         int i;
2587         int ret;
2588         int errors = 0;
2589         u32 crc;
2590         u64 bytenr;
2591
2592         if (max_mirrors == 0)
2593                 max_mirrors = BTRFS_SUPER_MIRROR_MAX;
2594
2595         for (i = 0; i < max_mirrors; i++) {
2596                 bytenr = btrfs_sb_offset(i);
2597                 if (bytenr + BTRFS_SUPER_INFO_SIZE >= device->total_bytes)
2598                         break;
2599
2600                 if (wait) {
2601                         bh = __find_get_block(device->bdev, bytenr / 4096,
2602                                               BTRFS_SUPER_INFO_SIZE);
2603                         BUG_ON(!bh);
2604                         wait_on_buffer(bh);
2605                         if (!buffer_uptodate(bh))
2606                                 errors++;
2607
2608                         /* drop our reference */
2609                         brelse(bh);
2610
2611                         /* drop the reference from the wait == 0 run */
2612                         brelse(bh);
2613                         continue;
2614                 } else {
2615                         btrfs_set_super_bytenr(sb, bytenr);
2616
2617                         crc = ~(u32)0;
2618                         crc = btrfs_csum_data(NULL, (char *)sb +
2619                                               BTRFS_CSUM_SIZE, crc,
2620                                               BTRFS_SUPER_INFO_SIZE -
2621                                               BTRFS_CSUM_SIZE);
2622                         btrfs_csum_final(crc, sb->csum);
2623
2624                         /*
2625                          * one reference for us, and we leave it for the
2626                          * caller
2627                          */
2628                         bh = __getblk(device->bdev, bytenr / 4096,
2629                                       BTRFS_SUPER_INFO_SIZE);
2630                         memcpy(bh->b_data, sb, BTRFS_SUPER_INFO_SIZE);
2631
2632                         /* one reference for submit_bh */
2633                         get_bh(bh);
2634
2635                         set_buffer_uptodate(bh);
2636                         lock_buffer(bh);
2637                         bh->b_end_io = btrfs_end_buffer_write_sync;
2638                 }
2639
2640                 /*
2641                  * we fua the first super.  The others we allow
2642                  * to go down lazy.
2643                  */
2644                 ret = submit_bh(WRITE_FUA, bh);
2645                 if (ret)
2646                         errors++;
2647         }
2648         return errors < i ? 0 : -1;
2649 }
2650
2651 /*
2652  * endio for the write_dev_flush, this will wake anyone waiting
2653  * for the barrier when it is done
2654  */
2655 static void btrfs_end_empty_barrier(struct bio *bio, int err)
2656 {
2657         if (err) {
2658                 if (err == -EOPNOTSUPP)
2659                         set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
2660                 clear_bit(BIO_UPTODATE, &bio->bi_flags);
2661         }
2662         if (bio->bi_private)
2663                 complete(bio->bi_private);
2664         bio_put(bio);
2665 }
2666
2667 /*
2668  * trigger flushes for one the devices.  If you pass wait == 0, the flushes are
2669  * sent down.  With wait == 1, it waits for the previous flush.
2670  *
2671  * any device where the flush fails with eopnotsupp are flagged as not-barrier
2672  * capable
2673  */
2674 static int write_dev_flush(struct btrfs_device *device, int wait)
2675 {
2676         struct bio *bio;
2677         int ret = 0;
2678
2679         if (device->nobarriers)
2680                 return 0;
2681
2682         if (wait) {
2683                 bio = device->flush_bio;
2684                 if (!bio)
2685                         return 0;
2686
2687                 wait_for_completion(&device->flush_wait);
2688
2689                 if (bio_flagged(bio, BIO_EOPNOTSUPP)) {
2690                         printk("btrfs: disabling barriers on dev %s\n",
2691                                device->name);
2692                         device->nobarriers = 1;
2693                 }
2694                 if (!bio_flagged(bio, BIO_UPTODATE)) {
2695                         ret = -EIO;
2696                 }
2697
2698                 /* drop the reference from the wait == 0 run */
2699                 bio_put(bio);
2700                 device->flush_bio = NULL;
2701
2702                 return ret;
2703         }
2704
2705         /*
2706          * one reference for us, and we leave it for the
2707          * caller
2708          */
2709         device->flush_bio = NULL;;
2710         bio = bio_alloc(GFP_NOFS, 0);
2711         if (!bio)
2712                 return -ENOMEM;
2713
2714         bio->bi_end_io = btrfs_end_empty_barrier;
2715         bio->bi_bdev = device->bdev;
2716         init_completion(&device->flush_wait);
2717         bio->bi_private = &device->flush_wait;
2718         device->flush_bio = bio;
2719
2720         bio_get(bio);
2721         submit_bio(WRITE_FLUSH, bio);
2722
2723         return 0;
2724 }
2725
2726 /*
2727  * send an empty flush down to each device in parallel,
2728  * then wait for them
2729  */
2730 static int barrier_all_devices(struct btrfs_fs_info *info)
2731 {
2732         struct list_head *head;
2733         struct btrfs_device *dev;
2734         int errors = 0;
2735         int ret;
2736
2737         /* send down all the barriers */
2738         head = &info->fs_devices->devices;
2739         list_for_each_entry_rcu(dev, head, dev_list) {
2740                 if (!dev->bdev) {
2741                         errors++;
2742                         continue;
2743                 }
2744                 if (!dev->in_fs_metadata || !dev->writeable)
2745                         continue;
2746
2747                 ret = write_dev_flush(dev, 0);
2748                 if (ret)
2749                         errors++;
2750         }
2751
2752         /* wait for all the barriers */
2753         list_for_each_entry_rcu(dev, head, dev_list) {
2754                 if (!dev->bdev) {
2755                         errors++;
2756                         continue;
2757                 }
2758                 if (!dev->in_fs_metadata || !dev->writeable)
2759                         continue;
2760
2761                 ret = write_dev_flush(dev, 1);
2762                 if (ret)
2763                         errors++;
2764         }
2765         if (errors)
2766                 return -EIO;
2767         return 0;
2768 }
2769
2770 int write_all_supers(struct btrfs_root *root, int max_mirrors)
2771 {
2772         struct list_head *head;
2773         struct btrfs_device *dev;
2774         struct btrfs_super_block *sb;
2775         struct btrfs_dev_item *dev_item;
2776         int ret;
2777         int do_barriers;
2778         int max_errors;
2779         int total_errors = 0;
2780         u64 flags;
2781
2782         max_errors = btrfs_super_num_devices(root->fs_info->super_copy) - 1;
2783         do_barriers = !btrfs_test_opt(root, NOBARRIER);
2784         backup_super_roots(root->fs_info);
2785
2786         sb = root->fs_info->super_for_commit;
2787         dev_item = &sb->dev_item;
2788
2789         mutex_lock(&root->fs_info->fs_devices->device_list_mutex);
2790         head = &root->fs_info->fs_devices->devices;
2791
2792         if (do_barriers)
2793                 barrier_all_devices(root->fs_info);
2794
2795         list_for_each_entry_rcu(dev, head, dev_list) {
2796                 if (!dev->bdev) {
2797                         total_errors++;
2798                         continue;
2799                 }
2800                 if (!dev->in_fs_metadata || !dev->writeable)
2801                         continue;
2802
2803                 btrfs_set_stack_device_generation(dev_item, 0);
2804                 btrfs_set_stack_device_type(dev_item, dev->type);
2805                 btrfs_set_stack_device_id(dev_item, dev->devid);
2806                 btrfs_set_stack_device_total_bytes(dev_item, dev->total_bytes);
2807                 btrfs_set_stack_device_bytes_used(dev_item, dev->bytes_used);
2808                 btrfs_set_stack_device_io_align(dev_item, dev->io_align);
2809                 btrfs_set_stack_device_io_width(dev_item, dev->io_width);
2810                 btrfs_set_stack_device_sector_size(dev_item, dev->sector_size);
2811                 memcpy(dev_item->uuid, dev->uuid, BTRFS_UUID_SIZE);
2812                 memcpy(dev_item->fsid, dev->fs_devices->fsid, BTRFS_UUID_SIZE);
2813
2814                 flags = btrfs_super_flags(sb);
2815                 btrfs_set_super_flags(sb, flags | BTRFS_HEADER_FLAG_WRITTEN);
2816
2817                 ret = write_dev_supers(dev, sb, do_barriers, 0, max_mirrors);
2818                 if (ret)
2819                         total_errors++;
2820         }
2821         if (total_errors > max_errors) {
2822                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2823                        total_errors);
2824                 BUG();
2825         }
2826
2827         total_errors = 0;
2828         list_for_each_entry_rcu(dev, head, dev_list) {
2829                 if (!dev->bdev)
2830                         continue;
2831                 if (!dev->in_fs_metadata || !dev->writeable)
2832                         continue;
2833
2834                 ret = write_dev_supers(dev, sb, do_barriers, 1, max_mirrors);
2835                 if (ret)
2836                         total_errors++;
2837         }
2838         mutex_unlock(&root->fs_info->fs_devices->device_list_mutex);
2839         if (total_errors > max_errors) {
2840                 printk(KERN_ERR "btrfs: %d errors while writing supers\n",
2841                        total_errors);
2842                 BUG();
2843         }
2844         return 0;
2845 }
2846
2847 int write_ctree_super(struct btrfs_trans_handle *trans,
2848                       struct btrfs_root *root, int max_mirrors)
2849 {
2850         int ret;
2851
2852         ret = write_all_supers(root, max_mirrors);
2853         return ret;
2854 }
2855
2856 int btrfs_free_fs_root(struct btrfs_fs_info *fs_info, struct btrfs_root *root)
2857 {
2858         spin_lock(&fs_info->fs_roots_radix_lock);
2859         radix_tree_delete(&fs_info->fs_roots_radix,
2860                           (unsigned long)root->root_key.objectid);
2861         spin_unlock(&fs_info->fs_roots_radix_lock);
2862
2863         if (btrfs_root_refs(&root->root_item) == 0)
2864                 synchronize_srcu(&fs_info->subvol_srcu);
2865
2866         __btrfs_remove_free_space_cache(root->free_ino_pinned);
2867         __btrfs_remove_free_space_cache(root->free_ino_ctl);
2868         free_fs_root(root);
2869         return 0;
2870 }
2871
2872 static void free_fs_root(struct btrfs_root *root)
2873 {
2874         iput(root->cache_inode);
2875         WARN_ON(!RB_EMPTY_ROOT(&root->inode_tree));
2876         if (root->anon_dev)
2877                 free_anon_bdev(root->anon_dev);
2878         free_extent_buffer(root->node);
2879         free_extent_buffer(root->commit_root);
2880         kfree(root->free_ino_ctl);
2881         kfree(root->free_ino_pinned);
2882         kfree(root->name);
2883         kfree(root);
2884 }
2885
2886 static int del_fs_roots(struct btrfs_fs_info *fs_info)
2887 {
2888         int ret;
2889         struct btrfs_root *gang[8];
2890         int i;
2891
2892         while (!list_empty(&fs_info->dead_roots)) {
2893                 gang[0] = list_entry(fs_info->dead_roots.next,
2894                                      struct btrfs_root, root_list);
2895                 list_del(&gang[0]->root_list);
2896
2897                 if (gang[0]->in_radix) {
2898                         btrfs_free_fs_root(fs_info, gang[0]);
2899                 } else {
2900                         free_extent_buffer(gang[0]->node);
2901                         free_extent_buffer(gang[0]->commit_root);
2902                         kfree(gang[0]);
2903                 }
2904         }
2905
2906         while (1) {
2907                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2908                                              (void **)gang, 0,
2909                                              ARRAY_SIZE(gang));
2910                 if (!ret)
2911                         break;
2912                 for (i = 0; i < ret; i++)
2913                         btrfs_free_fs_root(fs_info, gang[i]);
2914         }
2915         return 0;
2916 }
2917
2918 int btrfs_cleanup_fs_roots(struct btrfs_fs_info *fs_info)
2919 {
2920         u64 root_objectid = 0;
2921         struct btrfs_root *gang[8];
2922         int i;
2923         int ret;
2924
2925         while (1) {
2926                 ret = radix_tree_gang_lookup(&fs_info->fs_roots_radix,
2927                                              (void **)gang, root_objectid,
2928                                              ARRAY_SIZE(gang));
2929                 if (!ret)
2930                         break;
2931
2932                 root_objectid = gang[ret - 1]->root_key.objectid + 1;
2933                 for (i = 0; i < ret; i++) {
2934                         int err;
2935
2936                         root_objectid = gang[i]->root_key.objectid;
2937                         err = btrfs_orphan_cleanup(gang[i]);
2938                         if (err)
2939                                 return err;
2940                 }
2941                 root_objectid++;
2942         }
2943         return 0;
2944 }
2945
2946 int btrfs_commit_super(struct btrfs_root *root)
2947 {
2948         struct btrfs_trans_handle *trans;
2949         int ret;
2950
2951         mutex_lock(&root->fs_info->cleaner_mutex);
2952         btrfs_run_delayed_iputs(root);
2953         btrfs_clean_old_snapshots(root);
2954         mutex_unlock(&root->fs_info->cleaner_mutex);
2955
2956         /* wait until ongoing cleanup work done */
2957         down_write(&root->fs_info->cleanup_work_sem);
2958         up_write(&root->fs_info->cleanup_work_sem);
2959
2960         trans = btrfs_join_transaction(root);
2961         if (IS_ERR(trans))
2962                 return PTR_ERR(trans);
2963         ret = btrfs_commit_transaction(trans, root);
2964         BUG_ON(ret);
2965         /* run commit again to drop the original snapshot */
2966         trans = btrfs_join_transaction(root);
2967         if (IS_ERR(trans))
2968                 return PTR_ERR(trans);
2969         btrfs_commit_transaction(trans, root);
2970         ret = btrfs_write_and_wait_transaction(NULL, root);
2971         BUG_ON(ret);
2972
2973         ret = write_ctree_super(NULL, root, 0);
2974         return ret;
2975 }
2976
2977 int close_ctree(struct btrfs_root *root)
2978 {
2979         struct btrfs_fs_info *fs_info = root->fs_info;
2980         int ret;
2981
2982         fs_info->closing = 1;
2983         smp_mb();
2984
2985         /* pause restriper - we want to resume on mount */
2986         btrfs_pause_balance(root->fs_info);
2987
2988         btrfs_scrub_cancel(root);
2989
2990         /* wait for any defraggers to finish */
2991         wait_event(fs_info->transaction_wait,
2992                    (atomic_read(&fs_info->defrag_running) == 0));
2993
2994         /* clear out the rbtree of defraggable inodes */
2995         btrfs_run_defrag_inodes(root->fs_info);
2996
2997         /*
2998          * Here come 2 situations when btrfs is broken to flip readonly:
2999          *
3000          * 1. when btrfs flips readonly somewhere else before
3001          * btrfs_commit_super, sb->s_flags has MS_RDONLY flag,
3002          * and btrfs will skip to write sb directly to keep
3003          * ERROR state on disk.
3004          *
3005          * 2. when btrfs flips readonly just in btrfs_commit_super,
3006          * and in such case, btrfs cannot write sb via btrfs_commit_super,
3007          * and since fs_state has been set BTRFS_SUPER_FLAG_ERROR flag,
3008          * btrfs will cleanup all FS resources first and write sb then.
3009          */
3010         if (!(fs_info->sb->s_flags & MS_RDONLY)) {
3011                 ret = btrfs_commit_super(root);
3012                 if (ret)
3013                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
3014         }
3015
3016         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
3017                 ret = btrfs_error_commit_super(root);
3018                 if (ret)
3019                         printk(KERN_ERR "btrfs: commit super ret %d\n", ret);
3020         }
3021
3022         btrfs_put_block_group_cache(fs_info);
3023
3024         kthread_stop(root->fs_info->transaction_kthread);
3025         kthread_stop(root->fs_info->cleaner_kthread);
3026
3027         fs_info->closing = 2;
3028         smp_mb();
3029
3030         if (fs_info->delalloc_bytes) {
3031                 printk(KERN_INFO "btrfs: at unmount delalloc count %llu\n",
3032                        (unsigned long long)fs_info->delalloc_bytes);
3033         }
3034         if (fs_info->total_ref_cache_size) {
3035                 printk(KERN_INFO "btrfs: at umount reference cache size %llu\n",
3036                        (unsigned long long)fs_info->total_ref_cache_size);
3037         }
3038
3039         free_extent_buffer(fs_info->extent_root->node);
3040         free_extent_buffer(fs_info->extent_root->commit_root);
3041         free_extent_buffer(fs_info->tree_root->node);
3042         free_extent_buffer(fs_info->tree_root->commit_root);
3043         free_extent_buffer(root->fs_info->chunk_root->node);
3044         free_extent_buffer(root->fs_info->chunk_root->commit_root);
3045         free_extent_buffer(root->fs_info->dev_root->node);
3046         free_extent_buffer(root->fs_info->dev_root->commit_root);
3047         free_extent_buffer(root->fs_info->csum_root->node);
3048         free_extent_buffer(root->fs_info->csum_root->commit_root);
3049
3050         btrfs_free_block_groups(root->fs_info);
3051
3052         del_fs_roots(fs_info);
3053
3054         iput(fs_info->btree_inode);
3055
3056         btrfs_stop_workers(&fs_info->generic_worker);
3057         btrfs_stop_workers(&fs_info->fixup_workers);
3058         btrfs_stop_workers(&fs_info->delalloc_workers);
3059         btrfs_stop_workers(&fs_info->workers);
3060         btrfs_stop_workers(&fs_info->endio_workers);
3061         btrfs_stop_workers(&fs_info->endio_meta_workers);
3062         btrfs_stop_workers(&fs_info->endio_meta_write_workers);
3063         btrfs_stop_workers(&fs_info->endio_write_workers);
3064         btrfs_stop_workers(&fs_info->endio_freespace_worker);
3065         btrfs_stop_workers(&fs_info->submit_workers);
3066         btrfs_stop_workers(&fs_info->delayed_workers);
3067         btrfs_stop_workers(&fs_info->caching_workers);
3068         btrfs_stop_workers(&fs_info->readahead_workers);
3069
3070         btrfs_close_devices(fs_info->fs_devices);
3071         btrfs_mapping_tree_free(&fs_info->mapping_tree);
3072
3073         bdi_destroy(&fs_info->bdi);
3074         cleanup_srcu_struct(&fs_info->subvol_srcu);
3075
3076         free_fs_info(fs_info);
3077
3078         return 0;
3079 }
3080
3081 int btrfs_buffer_uptodate(struct extent_buffer *buf, u64 parent_transid)
3082 {
3083         int ret;
3084         struct inode *btree_inode = buf->first_page->mapping->host;
3085
3086         ret = extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree, buf,
3087                                      NULL);
3088         if (!ret)
3089                 return ret;
3090
3091         ret = verify_parent_transid(&BTRFS_I(btree_inode)->io_tree, buf,
3092                                     parent_transid);
3093         return !ret;
3094 }
3095
3096 int btrfs_set_buffer_uptodate(struct extent_buffer *buf)
3097 {
3098         struct inode *btree_inode = buf->first_page->mapping->host;
3099         return set_extent_buffer_uptodate(&BTRFS_I(btree_inode)->io_tree,
3100                                           buf);
3101 }
3102
3103 void btrfs_mark_buffer_dirty(struct extent_buffer *buf)
3104 {
3105         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
3106         u64 transid = btrfs_header_generation(buf);
3107         struct inode *btree_inode = root->fs_info->btree_inode;
3108         int was_dirty;
3109
3110         btrfs_assert_tree_locked(buf);
3111         if (transid != root->fs_info->generation) {
3112                 printk(KERN_CRIT "btrfs transid mismatch buffer %llu, "
3113                        "found %llu running %llu\n",
3114                         (unsigned long long)buf->start,
3115                         (unsigned long long)transid,
3116                         (unsigned long long)root->fs_info->generation);
3117                 WARN_ON(1);
3118         }
3119         was_dirty = set_extent_buffer_dirty(&BTRFS_I(btree_inode)->io_tree,
3120                                             buf);
3121         if (!was_dirty) {
3122                 spin_lock(&root->fs_info->delalloc_lock);
3123                 root->fs_info->dirty_metadata_bytes += buf->len;
3124                 spin_unlock(&root->fs_info->delalloc_lock);
3125         }
3126 }
3127
3128 void btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
3129 {
3130         /*
3131          * looks as though older kernels can get into trouble with
3132          * this code, they end up stuck in balance_dirty_pages forever
3133          */
3134         u64 num_dirty;
3135         unsigned long thresh = 32 * 1024 * 1024;
3136
3137         if (current->flags & PF_MEMALLOC)
3138                 return;
3139
3140         btrfs_balance_delayed_items(root);
3141
3142         num_dirty = root->fs_info->dirty_metadata_bytes;
3143
3144         if (num_dirty > thresh) {
3145                 balance_dirty_pages_ratelimited_nr(
3146                                    root->fs_info->btree_inode->i_mapping, 1);
3147         }
3148         return;
3149 }
3150
3151 void __btrfs_btree_balance_dirty(struct btrfs_root *root, unsigned long nr)
3152 {
3153         /*
3154          * looks as though older kernels can get into trouble with
3155          * this code, they end up stuck in balance_dirty_pages forever
3156          */
3157         u64 num_dirty;
3158         unsigned long thresh = 32 * 1024 * 1024;
3159
3160         if (current->flags & PF_MEMALLOC)
3161                 return;
3162
3163         num_dirty = root->fs_info->dirty_metadata_bytes;
3164
3165         if (num_dirty > thresh) {
3166                 balance_dirty_pages_ratelimited_nr(
3167                                    root->fs_info->btree_inode->i_mapping, 1);
3168         }
3169         return;
3170 }
3171
3172 int btrfs_read_buffer(struct extent_buffer *buf, u64 parent_transid)
3173 {
3174         struct btrfs_root *root = BTRFS_I(buf->first_page->mapping->host)->root;
3175         int ret;
3176         ret = btree_read_extent_buffer_pages(root, buf, 0, parent_transid);
3177         if (ret == 0)
3178                 set_bit(EXTENT_BUFFER_UPTODATE, &buf->bflags);
3179         return ret;
3180 }
3181
3182 static int btree_lock_page_hook(struct page *page, void *data,
3183                                 void (*flush_fn)(void *))
3184 {
3185         struct inode *inode = page->mapping->host;
3186         struct btrfs_root *root = BTRFS_I(inode)->root;
3187         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
3188         struct extent_buffer *eb;
3189         unsigned long len;
3190         u64 bytenr = page_offset(page);
3191
3192         if (page->private == EXTENT_PAGE_PRIVATE)
3193                 goto out;
3194
3195         len = page->private >> 2;
3196         eb = find_extent_buffer(io_tree, bytenr, len);
3197         if (!eb)
3198                 goto out;
3199
3200         if (!btrfs_try_tree_write_lock(eb)) {
3201                 flush_fn(data);
3202                 btrfs_tree_lock(eb);
3203         }
3204         btrfs_set_header_flag(eb, BTRFS_HEADER_FLAG_WRITTEN);
3205
3206         if (test_and_clear_bit(EXTENT_BUFFER_DIRTY, &eb->bflags)) {
3207                 spin_lock(&root->fs_info->delalloc_lock);
3208                 if (root->fs_info->dirty_metadata_bytes >= eb->len)
3209                         root->fs_info->dirty_metadata_bytes -= eb->len;
3210                 else
3211                         WARN_ON(1);
3212                 spin_unlock(&root->fs_info->delalloc_lock);
3213         }
3214
3215         btrfs_tree_unlock(eb);
3216         free_extent_buffer(eb);
3217 out:
3218         if (!trylock_page(page)) {
3219                 flush_fn(data);
3220                 lock_page(page);
3221         }
3222         return 0;
3223 }
3224
3225 static void btrfs_check_super_valid(struct btrfs_fs_info *fs_info,
3226                               int read_only)
3227 {
3228         if (read_only)
3229                 return;
3230
3231         if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
3232                 printk(KERN_WARNING "warning: mount fs with errors, "
3233                        "running btrfsck is recommended\n");
3234 }
3235
3236 int btrfs_error_commit_super(struct btrfs_root *root)
3237 {
3238         int ret;
3239
3240         mutex_lock(&root->fs_info->cleaner_mutex);
3241         btrfs_run_delayed_iputs(root);
3242         mutex_unlock(&root->fs_info->cleaner_mutex);
3243
3244         down_write(&root->fs_info->cleanup_work_sem);
3245         up_write(&root->fs_info->cleanup_work_sem);
3246
3247         /* cleanup FS via transaction */
3248         btrfs_cleanup_transaction(root);
3249
3250         ret = write_ctree_super(NULL, root, 0);
3251
3252         return ret;
3253 }
3254
3255 static int btrfs_destroy_ordered_operations(struct btrfs_root *root)
3256 {
3257         struct btrfs_inode *btrfs_inode;
3258         struct list_head splice;
3259
3260         INIT_LIST_HEAD(&splice);
3261
3262         mutex_lock(&root->fs_info->ordered_operations_mutex);
3263         spin_lock(&root->fs_info->ordered_extent_lock);
3264
3265         list_splice_init(&root->fs_info->ordered_operations, &splice);
3266         while (!list_empty(&splice)) {
3267                 btrfs_inode = list_entry(splice.next, struct btrfs_inode,
3268                                          ordered_operations);
3269
3270                 list_del_init(&btrfs_inode->ordered_operations);
3271
3272                 btrfs_invalidate_inodes(btrfs_inode->root);
3273         }
3274
3275         spin_unlock(&root->fs_info->ordered_extent_lock);
3276         mutex_unlock(&root->fs_info->ordered_operations_mutex);
3277
3278         return 0;
3279 }
3280
3281 static int btrfs_destroy_ordered_extents(struct btrfs_root *root)
3282 {
3283         struct list_head splice;
3284         struct btrfs_ordered_extent *ordered;
3285         struct inode *inode;
3286
3287         INIT_LIST_HEAD(&splice);
3288
3289         spin_lock(&root->fs_info->ordered_extent_lock);
3290
3291         list_splice_init(&root->fs_info->ordered_extents, &splice);
3292         while (!list_empty(&splice)) {
3293                 ordered = list_entry(splice.next, struct btrfs_ordered_extent,
3294                                      root_extent_list);
3295
3296                 list_del_init(&ordered->root_extent_list);
3297                 atomic_inc(&ordered->refs);
3298
3299                 /* the inode may be getting freed (in sys_unlink path). */
3300                 inode = igrab(ordered->inode);
3301
3302                 spin_unlock(&root->fs_info->ordered_extent_lock);
3303                 if (inode)
3304                         iput(inode);
3305
3306                 atomic_set(&ordered->refs, 1);
3307                 btrfs_put_ordered_extent(ordered);
3308
3309                 spin_lock(&root->fs_info->ordered_extent_lock);
3310         }
3311
3312         spin_unlock(&root->fs_info->ordered_extent_lock);
3313
3314         return 0;
3315 }
3316
3317 static int btrfs_destroy_delayed_refs(struct btrfs_transaction *trans,
3318                                       struct btrfs_root *root)
3319 {
3320         struct rb_node *node;
3321         struct btrfs_delayed_ref_root *delayed_refs;
3322         struct btrfs_delayed_ref_node *ref;
3323         int ret = 0;
3324
3325         delayed_refs = &trans->delayed_refs;
3326
3327         spin_lock(&delayed_refs->lock);
3328         if (delayed_refs->num_entries == 0) {
3329                 spin_unlock(&delayed_refs->lock);
3330                 printk(KERN_INFO "delayed_refs has NO entry\n");
3331                 return ret;
3332         }
3333
3334         node = rb_first(&delayed_refs->root);
3335         while (node) {
3336                 ref = rb_entry(node, struct btrfs_delayed_ref_node, rb_node);
3337                 node = rb_next(node);
3338
3339                 ref->in_tree = 0;
3340                 rb_erase(&ref->rb_node, &delayed_refs->root);
3341                 delayed_refs->num_entries--;
3342
3343                 atomic_set(&ref->refs, 1);
3344                 if (btrfs_delayed_ref_is_head(ref)) {
3345                         struct btrfs_delayed_ref_head *head;
3346
3347                         head = btrfs_delayed_node_to_head(ref);
3348                         mutex_lock(&head->mutex);
3349                         kfree(head->extent_op);
3350                         delayed_refs->num_heads--;
3351                         if (list_empty(&head->cluster))
3352                                 delayed_refs->num_heads_ready--;
3353                         list_del_init(&head->cluster);
3354                         mutex_unlock(&head->mutex);
3355                 }
3356
3357                 spin_unlock(&delayed_refs->lock);
3358                 btrfs_put_delayed_ref(ref);
3359
3360                 cond_resched();
3361                 spin_lock(&delayed_refs->lock);
3362         }
3363
3364         spin_unlock(&delayed_refs->lock);
3365
3366         return ret;
3367 }
3368
3369 static int btrfs_destroy_pending_snapshots(struct btrfs_transaction *t)
3370 {
3371         struct btrfs_pending_snapshot *snapshot;
3372         struct list_head splice;
3373
3374         INIT_LIST_HEAD(&splice);
3375
3376         list_splice_init(